Next Article in Journal
From Protosolar Space to Space Exploration: The Role of Graphene in Space Technology and Economy
Next Article in Special Issue
Boosting the Catalytic Performance of AuAg Alloyed Nanoparticles Grafted on MoS2 Nanoflowers through NIR-Induced Light-to-Thermal Energy Conversion
Previous Article in Journal
Construction of Nanostructured Glass-Zirconia to Improve the Interface Stability of Dental Bilayer Zirconia
Previous Article in Special Issue
Fabrication of Novel Heterostructure-Functionalized Graphene-Based TiO2-Sr-Hexaferrite Photocatalyst for Environmental Remediation
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Nanomaterials
Volume 13
Issue 4
10.3390/nano13040679
nanomaterials-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Methanol and Ethanol Electrooxidation on ZrO2/NiO/rGO

by
Mohammad Bagher Askari
1,
Hadi Beitollahi
2,* and
Antonio Di Bartolomeo
3,*
1
Department of Semiconductor, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631818356, Iran
2
Environment Department, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631885356, Iran
3
Department of Physics “E. R. Caianiello” and “Interdepartmental Center NANOMATES”, University of Salerno, Fisciano 84084, Salerno, Italy
*
Authors to whom correspondence should be addressed.
Nanomaterials 2023, 13(4), 679; https://doi.org/10.3390/nano13040679
Submission received: 14 December 2022 / Revised: 4 February 2023 / Accepted: 6 February 2023 / Published: 9 February 2023
(This article belongs to the Special Issue Synthesis of Nanocomposites and Catalysis Applications II)
Browse Figures
Versions Notes

Abstract

:
Recently, transition metal oxides have been considered for various applications due to their unique properties. We present the synthesis of a three-component catalyst consisting of zirconium oxide (ZrO2), nickel oxide (NiO), and reduced graphene oxide (rGO) in the form of ZrO2/NiO/rGO by a simple one-step hydrothermal method. X-ray powder diffraction (XRD), scanning electron microscope (SEM), and bright-field transmission electron microscopy (BF-TEM) analyses were performed to accurately characterize the catalysts. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) analyses were also carried out to investigate the methanol and ethanol alcohol electrooxidation ability of the synthesized nanocatalysts. Inspired by the good potential of metal oxides in the field of catalysts, especially in fuel-cell anodes, we investigated the capability of this catalyst in the methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). After proving the successful synthesis and examining the surface morphology of these materials, detailed electrochemical tests were performed to show the outstanding capability of this new nanocatalyst for use in the anode of alcohol fuel cells. ZrO2/NiO/rGO indicated a current density of 26.6 mA/cm2 at a peak potential of 0.52 V and 99.5% cyclic stability in the MOR and a current density of 17.3 mA/cm2 at a peak potential of 0.52 V and 98.5% cyclic stability in the EOR (at optimal concentration/scan rate 20 mV/s), representing an attractive option for use in the anode of alcoholic fuel cells.

1. Introduction

Modern society and industry are highly dependent on electricity produced by fossil fuels for consumer and manufacturing tools [1,2]. Considering the destructive effect of the excessive use of fossil fuels on the environment and the health of society with the production of greenhouse gases and also the exhaustibility of these fuel sources, there is a strong need to find new clean fuels and renewable resources [3,4]. Different types of fuel cells, solar cells, electrochemical batteries, and supercapacitors are among the latest energy storage and production tools [5]. The industrialization of these devices and the detailed understanding of how energy is produced and stored require the involvement of different sciences. Indeed, this field is at the frontier of modern research and gathers the attention of many scientists, involved in activities that range from the catalyst and membrane synthesis to the assembling of equipment to be placed in portable devices and cars, etc.
There are different types of fuel cells, some of the most common ones are direct methanol fuel cells (DMFCs), polymer electrolyte membranes (PEMs), alkaline fuel cells (AFCs), phosphoric acid fuel cells (PAFCs), molten carbonate fuel cells (MCFCs), solid oxide fuel cells (SOFCs), and reversible fuel cells, whose main difference is in the operating temperature and the type of electro-chemical reactions, electrolytes, and fuel required and catalysts used in their anode and cathode. Alcohol fuel cells are particularly popular due to their low operating temperature [6], high energy density [7], and small dimensions. Among the fuels used in fuel cells, methanol and ethanol have attracted the attention of scientists due to their cheapness, availability, easy production, and safe storage and transportation [8,9,10]. However, the toxicity of methanol and the relatively low evaporation temperature of both alcohols are among the disadvantages of these fuels [11].
Fuel cells convert chemical energy into electrical energy [12]. In this regard, the oxidation of alcohols (methanol and ethanol) occurs in the anode, and oxygen reduction occurs in the cathode. Between the anode and the cathode, there is a polymer membrane, usually Nafion, which is responsible for proton exchange [13].
So far, valuable efforts have been made to introduce catalysts for use in the anode and cathode of alcohol fuel cells. Several efficient and engineered catalysts have been introduced; however, none of them can compete with catalysts such as platinum, palladium, and ruthenium. Alcohol fuel cells based on these catalysts are expensive and have a gradual loss of electrocatalytic activity in alcohol oxidation [14].
Three categories can be considered in the classification of catalysts for the oxidation process of alcohols. In the first category, there are catalysts such as platinum, palladium, and ruthenium in pure form and with different morphologies. Although they are very efficient, their high price is a big problem for commercialization. In the second category, very small amounts of expensive catalysts are combined or hybridized with cheap and electroactive materials such as conductive polymers, carbons, and metal-organic frameworks (MOFs). In this way, although efficiency decreases, the price of catalysts can be brought down significantly. The third category of attractive and inexpensive catalysts that cannot compete with platinum-based catalysts (and other related families) are platinum-free catalysts. In the synthesis process, it should be noted that the proposed catalyst must have two very important properties: a relatively high electrochemically active surface area and acceptable electrical conductivity. Among these catalysts, we can mention the combination of various materials such as metal oxides and sulfides, different types of carbons, conductive polymers, zeolites, and MOFs [15]. Metal oxides have shown good electrocatalytic activity. Their hybridization and composition with other materials can improve the electrochemically active surface area and electrical conductivity, thus paving the way for new inexpensive catalysts. Carbon, as one of the most abundant elements in nature, is always available, and the synthesis of its derivatives is not a difficult task. From carbon derivatives, we can mention multi-walled carbon nanotubes (MWCNTs), single-walled carbon nanotubes (SWCNTs), hollow carbon spheres (HCNS), biochar carbon, different types of activated carbon, and reduced graphene oxide (RGO). Each of the mentioned types of carbon when added to the catalyst structure improves electrical conductivity, increases the electrochemical active surface area of the catalyst, and generally facilitates the electrochemical processes. Composites consisting of several metal oxides and their hybrids with reduced graphene oxide (rGO) can be a suitable choice for the synthesis of new catalysts. In such catalysts, the synergistic effect of metal oxide and a type of carbon with an excellent active surface area and suitable electrical conductivity can also be exploited [16,17,18].
The review of new scientific studies shows that zirconium oxide (ZrO2) [19,20,21,22] and nickel oxide (NiO) [23,24,25] are among the most widely used catalysts based on metal oxides in various fields. The use of these catalysts in the structure of various types of solar cells [26], processes such as water splitting, hydrogen evolution reactions (HERs) [27], oxygen reduction reactions (ORRs) [28], etc., in the field of energy production, as well as the wide application of these materials in the structure of the electrodes of various types of electrochemical batteries, such as lithium, manganese, and zinc-air batteries [29,30], and in the structure electrodes of supercapacitors [31,32] in the field of energy storage, shows the wide capability of these materials in modern electrochemistry. In addition, we must mention the wide application of ZrO2 and NiO in other electrochemical applications such as electrochemical biosensors [33,34] and electrochemical detection of various drugs [35,36], antibacterial and photocatalytic properties [37,38,39], as well as in the oxidation process of many materials such as urea, glucose, various sugar alcohols, etc. [40,41].
ZrO2 and NiO as catalysts in the form of composites with other materials (both expensive catalysts such as platinum and palladium and other inexpensive materials and substrates, including metal oxides and sulfides or conductive polymers) have been studied for the oxidation of alcohols [22,42,43,44,45,46,47,48,49]. However, catalysts including both ZrO2 and NiO have not been tested in the oxidation of methanol and ethanol alcohols. For this purpose, we synthesized a nanocatalyst consisting of both zirconium and nickel metal oxides by a hydrothermal method. To simultaneously improve the electrical conductivity and the electrochemical active surface, a hybrid of ZrO2/NiO with reduced graphene oxide (rGO) was prepared in the same way and in one step. In this research, in addition to investigating the ability of ZrO2/NiO nanocatalysts in the oxidation process of methanol and ethanol alcohols, we investigated the improvement in catalyst performance by adding rGO to the ZrO2/NiO structure.

2. Materials and Methods

2.1. Materials and Equipment

All the materials used in this research, including zirconium nitrate Zr(NO3)4•5H2O and nickel nitrate Co(NO3)2•6H2O, PEG, H2O2, methanol, and potassium hydroxide (KOH) with purity > 99%, were purchased from Aldrich Company (Wyoming, IL, USA). X-ray diffraction (XRD) analysis was performed with an XRD device, Philips PW1800, and scanning electron microscope (SEM) images were prepared with SEM—TESCAN. Bright-field transmission electron microscopy (BF-TEM) was performed with JEM-1400Plus, with thermionic source (LaB6), operated at 120 kV. Electrochemical analyses were performed with the potentiostat/galvanostat Autolab 302 N (Herisau, Switzerland) with a three-electrode system.

2.2. Synthesis of Nanocatalysts

For the synthesis of ZrO2/NiO, 0.15 g of zirconium nitrate (Zr(NO3)4•5H2O) and 0.25 g of nickel nitrate (Ni(NO3)2·6H2O) were mixed in 30 mL of deionized water for 20 min with a magnetic stirrer. Then, 0.15 mL of PEG-400 solution and 0.1 mL of H2O2 were added to the solution, and stirring was continued for another 10 min. The resulting solution was poured into a reactor with a capacity of 50 mL and put in the oven for 14 h at a temperature of 200 °C. The reactor was cooled at room temperature. The product was washed several times with deionized water and ethanol and dried at 80 °C for 8 h and then calcined at 350 °C for 3 h. The resulting powder was ZrO2/NiO. For the synthesis of ZrO2/NiO/rGO, we followed exactly the same method as for the synthesis of ZrO2/NiO, with the difference that in the first, 0.2 g of graphene oxide (GO) was added to the zirconium and nickel precursors.

3. Results

3.1. Characterization of Nanocatalysts

To investigate the crystal structure and surface morphology of the synthesized nanocatalysts, X-ray diffraction (Figure 1) and SEM analyses (Figure 2) were performed, respectively. In the X-ray diffraction pattern of ZrO2/NiO (ZN), the characteristic peaks of ZrO2 are observed at the diffraction angles of 30, 35.2, 50.2, and 60.3, which correspond to the (111), (200), (220), and (311) crystal planes, which is in complete agreement with (JCPDS, No.49-1642) [48]. The diffraction angles of NiO are also seen at 37.2, 43.2, 62.9, 75.2, and 79.4, which correspond to the (111), (200), (220), (311), and (222) crystal planes with (JCPDS, No. 04-0835) [50]. In the XRD pattern of ZrO2/NiO/rGO (ZNR), in addition to observing the diffraction peaks of ZrO2 and NiO, we see a relatively wide peak at the diffraction angle around 26 degrees, which belongs to reduced graphene oxide [51].
Scanning electron microscope (SEM) images of ZrO2/NiO (ZN) and ZrO2/NiO/rGO (ZNR) catalysts were prepared to investigate the surface morphology. Figure 2a–c, b belong to the SEM images of ZrO2/NiO on the scale of 200 nm. The relatively porous morphology of this nanocatalyst is clear in these figures. The presence of porosity in the structure of the catalysts causes the creation of channels and shortcuts that facilitate the oxidation process of alcoholic fuels and a faster and deeper contact of the fuel with the core of the catalyst. The SEM images of the ZrO2/NiO/rGO catalyst are shown in Figure 2d–f at a scale of 500 nm. The ZrO2/NiO nanocatalyst was also analyzed by BF-TEM and mapping related to this analysis. Figure 2g shows the BF-TEM of the catalyst in two scales of 200 and 150 nm. By examining the mapping of ZrO2/NiO, which was performed at the scale of 250 nm, the presence of the zirconium, nickel, and oxygen elements in the structure of the catalyst is shown. In addition, the existence of two different structures of ZrO2 and NiO in the catalyst can also be found. The darker parts are related to ZrO2, and the relatively lighter parts are NiO.

3.2. Electrochemical Studies

3.2.1. Electrode Preparation

To perform electrochemical tests, a glassy carbon electrode (GCE) modified with a catalyst was used as a working electrode. A Ag/AgCl electrode and platinum wire with a diameter of 1 mm were used as reference and auxiliary electrodes, respectively. To prepare the working electrode, 0.08 g of catalysts (ZrO2/NiO and ZrO2/NiO/rGO) was dispersed in 0.5 mL of a solution containing water, Nafion (5%), and isopropyl alcohol by ultrasonication for 30 min. Then, 3 microliters of the obtained uniform slurry was put on the GCE surface.

3.2.2. Investigating the Behavior of ZrO2/NiO and ZrO2/NiO/rGO Nanocatalysts for MOR and EOR Processes in an Alkaline Environment

The electrochemical studies were started by performing cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses in an alkaline environment (0.5 M potassium hydroxide (KOH)). The CV analysis of the modified electrode with ZrO2/NiO (ZN) and ZrO2/NiO/rGO (ZNR) nanocatalysts in the potential range of 0 to 0.8 V with a scan rate of 20 mV/s is shown in Figure 3a. In these graphs, no oxidation peak is seen, and only a faradic current is observed, whose value for ZNR is higher than ZN. Figure 3b belongs to the EIS analysis and the equivalent circuit related to ZN and ZNR nanocatalysts in 0.5 M KOH (without the presence of methanol and ethanol alcohol). According to this analysis, the charge transfer resistance (Rct) for ZN is approximately 19 Ω, and for ZNR, it is about 12 Ω. Both CV and EIS analyses indicate an improvement in the electrocatalytic properties of ZNR nanocatalysts compared to ZN. This superiority in electrocatalytic activity can be related to the effective presence of rGO in the ZNR structure. rGO facilitates electrochemical processes by increasing the electrochemical active surface area and improving electrical conductivity [13,25].
In the next step, the behavior of the catalysts in the presence of 0.1 M methanol was investigated. According to Figure 3c, both nanocatalysts show an oxidation peak, which confirms their ability in the MOR process. Moreover, the ability of nanocatalysts in the EOR process was investigated with the same procedure. The electrochemical behavior of two nanocatalysts in an alkaline environment and in the presence of ethanol (0.5 M KOH/0.1 M ethanol) is presented in Figure 3d. Both nanocatalysts have a relatively good potential in the EOR process as confirmed by the presence of oxidation peaks.
In the following, the concentration of alcohols in the MOR and EOR processes was optimized by the electrode modified with two ZN and ZNR nanocatalysts. For this purpose, a solution containing 0.5 M KOH and different concentrations of methanol (0.1, 0.3, 0.5, 0.7, and 0.9 M) was prepared. Figure 4a shows the behavior of a ZN nanocatalyst in different concentrations of methanol in CV analysis at a scan rate of 20 mV/s. As can be seen, with the increase in the concentration of methanol up to 0.7 M, the oxidation peak has an upward trend, and at the concentration of 0.9 M methanol, the current density of the oxidation peak decreases; exactly the same trend is observed for ZNR (Figure 4b).
The behavior of both nanocatalysts was investigated in the alkaline environment of 0.5 M KOH and in different concentrations of ethanol (0.1, 0.3, 0.5, 0.7, and 0.9 M) at the scan rate of 20 mV/s. Figure 4c shows the behavior of ZN in different concentrations of ethanol. As can be seen, the oxidation current density has an upward behavior up to the concentration of 0.5 M ethanol, and from this concentration onward, a decrease in the current density is seen. A similar behavior is observed for ZNR in different concentrations of ethanol (Figure 4d).
In general, the behavior of both nanocatalysts in different concentrations of methanol and ethanol indicates that with the increase in the alcohol concentration up to a critical concentration, the peak oxidation current density value increases, and after this concentration, the catalyst surface seems to be saturated by the by-products of the ethanol and methanol oxidation, and as a result, alcohol fuel cannot adsorb well on the surface of the catalyst and penetrate into the core of the catalyst. By-products of the oxidation of alcohols by saturating the surface of the catalyst prevent the easy exchange of electrons and, as a result, avoid the generation of an exchange current between the modified electrode and the alkaline solution containing alcoholic fuels.
After optimizing the concentration of alcohols, the behavior of nanocatalysts in the optimal concentration of methanol and ethanol and at different scan rates was investigated. Figure 5a shows the behavior of ZN in 0.5 M KOH/0.7 M methanol solution at different scan rates (20, 40, 60, 80, and 100 mV/s). As can be seen, with the increase in the scan rate, the oxidation peak current density indicates an upward trend, and the same behavior is seen for ZNR nanocatalysts at different scan rates (Figure 5b). The maximum current density as a function of the square root of the scan rate (Figure 5c) for two nanocatalysts is fitted with a straight line with R2 = 0.998 and R2 = 0.996 for ZN and ZNR, indicating the diffusion-control mechanism in the MOR process.
The mechanism of the MOR by nanocatalysts can be proposed as a six-electron mechanism as follows [52]:
C a t a l y s t + C H 3 O H → C a t a l y s t − C H 3 O H a d s
C a t a l y s t − C H 3 O H a d s + 4 O H ¯ → C a t a l y s t − C O a d s + 4 H 2 O + 4 e ¯
C a t a l y s t + O H ¯ → C a t a l y s t − O H a d s + e ¯
C a t a l y s t − C O a d s + C a t a l y s t − O H a d s   + O H ¯   → C a t a l y s t + C O 2 + H 2 O + e ¯
Similarly, the behavior of ZN and ZNR nanocatalysts in a 0.5 M KOH/0.5 M ethanol solution and at different scan rates was evaluated. Here too, the peak oxidation current density of both nanocatalysts increases with an increasing scan rate in the range of 20 to 100 mV/s (Figure 5d,e). The straight-line fit (with R2 = 0.996 and R2 = 0.994 for ZN and ZNR, respectively) of the maximum current density versus the square of the scan rate in the EOR process shows the diffusion-control mechanism (Figure 5f).
The proposed mechanism of ethanol oxidation by nanocatalysts can be suggested as follows [53]:
C H 3 C H 2 O H + 16 O H −   →   2 C O 3 2 − + 11 H 2 O + 12 e −  
C H 3 C H 2 O H + 5 O H −   →   C H 3 C O O − + 4 H 2 O + 4 e −
The stability of ZN and ZNR nanocatalysts in the MOR and EOR processes was determined by performing 1000 consecutive CV cycles in a 0.5 M KOH/optimal concentration of alcohols and at a scan rate of 20 mV/s. Figure 6a,b are related to the stability of ZN and ZNR in the MOR process. ZN has 98.3% stability after 1000 consecutive cycles, and ZNR shows 99.5% stability, which are very good values.
Figure 6c,d show the stability of ZN and ZNR nanocatalysts in the EOR process after 1000 consecutive CV cycles. Cyclic stability after this number of cycles is 97.9% for ZN and 98.5% for ZNR.
By investigating the cyclic stability of nanocatalysts in the MOR and EOR processes, a drop in current density is observed in the initial cycles, but, after that, with the complete penetration of methanol and ethanol into the core and structure of the catalyst and full contact between them, very good stability in current density is achieved. The comparison of the stability of nanocatalysts in the MOR and EOR processes shows the relative superiority of ZNR nanocatalysts compared to ZN in terms of cyclic stability. This superiority can be related to the presence of RGO in the catalyst structure. By increasing the electrochemically active surface, rGO facilitates the oxidation process of alcohols, and by making its active surface available to the fuel, it causes faster cyclic stability of the nanocatalyst in the oxidation process.
The behavior of catalysts in the process of methanol and ethanol oxidation at different temperatures was investigated by performing linear sweep voltammetry (LSV) analysis at a scan rate of 20 mV/s and in the temperature range of ambient temperature up to 45 °C. An increase in temperature improves the oxidation process of alcohols, and according to the linear relationship between temperature and current density, an increase in the peak oxidation current density is observed with increasing temperature. Figure 7a,b show the behavior of ZN and ZNR nanocatalysts at different temperatures. The increase in temperature facilitates the kinetics of the MOR and, as a result, increases current density. In the process of ethanol oxidation, the same behavior is observed for ZN and ZNR nanocatalysts at different temperatures (Figure 7c,d). The linear relationship between temperature and current density can be observed in the LSV diagrams. Hence, an increase in the oxidation current density occurs in both methanol and ethanol oxidation processes with the rising temperature.
In Table 1, the efficiency of the ZrO2/NiO/rGO nanocatalyst in the methanol and ethanol oxidation process is compared with other recent articles. The oxidation peak potential and current density of ZrO2/NiO/rGO are comparable with other similar works.

4. Conclusions

Due to their high electrocatalytic activities, zirconium oxide and nickel oxide were combined with reduced graphene oxide to form novel catalysts. Adding rGO to the catalyst structure facilitates the oxidation process of alcohols. We investigated the behavior of ZrO2/NiO and ZrO2/NiO/rGO in the MOR and EOR processes. We demonstrated that ZrO2/NiO/rGO is an attractive, cheap, and stable nanocatalyst with a relatively easy synthesis. It is worth mentioning that although these new nanocatalysts cannot compete yet with catalysts based on noble and expensive metals, such as platinum, ruthenium, and palladium, they can offer a good option for alcohol oxidation in fuel cells. The methanol and ethanol current densities obtained for ZrO2/NiO/rGO were 26.6 mA/cm2 and 17.3 mA/cm2, respectively. The interesting point is that the potential peak for both processes is seen at approximately 0.52 V, and the proposed catalyst has very good stability in both MOR and EOR processes. Considering that ZrO2 and NiO have always been prominent in the field of catalysts and have shown very good electrocatalytic activity, our research team aims to investigate the capability of these catalysts in different fields of energy and electrochemical determination of some drugs and alcohol in our future studies. The preliminary results of the performed electrochemical analyses show the excellent potential of this catalyst in the process of oxidation and sensing of sorbitol, urea, glycerol, and glucose. Moreover, the ability of this material as a supercapacitor electrode and electrochemical battery can also be evaluated.

Author Contributions

Conceptualization, H.B. and A.D.B.; methodology, M.B.A.; software, M.B.A.; validation, H.B. and A.D.B.; formal analysis, M.B.A., H.B. and A.D.B.; investigation, M.B.A., H.B. and A.D.B.; resources, H.B. and A.D.B.; data curation, M.B.A. and H.B.; writing—original draft preparation, M.B.A. and H.B.; writing—review and editing, A.D.B.; visualization, M.B.A.; supervision, H.B. and A.D.B.; project administration, H.B.; funding acquisition, H.B. and A.D.B. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the University of Salerno, grant number ORSA223384. The APC was funded by A.D.B.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding authors.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Ahmad, T.; Zhang, D.; Huang, C.; Zhang, H.; Dai, N.; Song, Y.; Chen, H. Artificial intelligence in sustainable energy industry: Status Quo, challenges and opportunities. J. Clean. Prod. 2021, 289, 125834. [Google Scholar] [CrossRef]
  2. Phuyal, S.; Bista, D.; Bista, R. Challenges, Opportunities and Future Directions of Smart Manufacturing: A State of Art Review. Sustain. Futur. 2020, 2, 100023. [Google Scholar] [CrossRef]
  3. Singh, S. Energy Crisis and Climate Change: Global Concerns and Their Solutions. In Energy: Crises, Challenges and Solutions; Wiley: New York, NY, USA, 2021; pp. 1–17. [Google Scholar]
  4. Wei, X.; Mohsin, M.; Zhang, Q. Role of foreign direct investment and economic growth in renewable energy development. Renew. Energy 2022, 192, 828–837. [Google Scholar]
  5. Askari, M.; Rozati, S.; Di Bartolomeo, A. Fabrication of Mn3O4-CeO2-rGO as Nanocatalyst for Electro-Oxidation of Methanol. Nanomaterials 2022, 12, 1187. [Google Scholar] [PubMed]
  6. Kishore, S.C.; Perumal, S.; Atchudan, R.; Alagan, M.; Sundramoorthy, A.K.; Lee, Y.R. A Critical Review on Artificial Intelligence for Fuel Cell Diagnosis. Catalysts 2022, 12, 743. [Google Scholar] [CrossRef]
  7. Xia, Z.; Zhang, X.; Sun, H.; Wang, S.; Sun, G. Recent advances in multi-scale design and construction of materials for direct methanol fuel cells. Nano Energy 2019, 65, 104048. [Google Scholar] [CrossRef]
  8. Fan, Y.; Yang, B.; Rong, C. Functionalized carbon nanomaterials for advanced anode catalysts of fuel cells. In Advanced Nanomaterials for Electrochemical-Based Energy Conversion and Storage; Elsevier: Amsterdam, The Netherlands, 2020; pp. 223–263. [Google Scholar]
  9. Moghadam, M.T.T.; Seifi, M.; Askari, M.B.; Azizi, S. ZnO-MWCNT@ Fe3O4 as a novel catalyst for methanol and ethanol oxidation. J. Phys. Chem. Solids. 2022, 165, 110688. [Google Scholar] [CrossRef]
  10. Pirzadi, Z.; Meshkani, F. From glycerol production to its value-added uses: A critical review. Fuel 2022, 329, 125044. [Google Scholar]
  11. Bansal, P.; Meena, R. Methanol as an Alternative Fuel in Internal Combustion Engine: Scope, Production, and Limitations. In Methanol: A Sustainable Transport Fuel for SI Engines; Springer: Singapore, 2021; pp. 11–36. [Google Scholar]
  12. Salarizadeh, P.; Askari, M.B.; Di Bartolomeo, A. MoS2/Ni3S2/Reduced graphene oxide nanostructure as an electrocatalyst for alcohol fuel cells. ACS Appl. Nano Mater. 2022, 5, 3361–3373. [Google Scholar]
  13. Askari, M.B.; Salarizadeh, P.; Di Bartolomeo, A.; Zadeh, M.H.R.; Beitollahi, H.; Tajik, S. Hierarchical nanostructures of MgCo2O4 on reduced graphene oxide as a high-performance catalyst for methanol electro-oxidation. Ceram. Int. 2021, 47, 16079–16085. [Google Scholar] [CrossRef]
  14. Ramli, Z.A.C.; Shaari, N.; Saharuddin, T.S.T. Progress and major BARRIERS of nanocatalyst development in direct methanol fuel cell: A review. Int. J. Hydrogen Energy 2022, 47, 22114–22146. [Google Scholar] [CrossRef]
  15. Dourandish, Z.; Tajik, S.; Beitollahi, H.; Jahani, P.M.; Nejad, F.G.; Sheikhshoaie, I.; Di Bartolomeo, A. A Comprehensive Review of Metal–Organic Framework: Synthesis, Characterization, and Investigation of Their Application in Electrochemical Biosensors for Biomedical Analysis. Sensors 2022, 22, 2238. [Google Scholar] [CrossRef] [PubMed]
  16. Masa, J.; Schuhmann, W. The role of non-metallic and metalloid elements on the electrocatalytic activity of cobalt and nickel catalysts for the oxygen evolution reaction. ChemCatChem 2019, 11, 5842–5854. [Google Scholar] [CrossRef] [Green Version]
  17. Santos, G.O.S.; Silva, L.R.A.; Alves, Y.G.S.; Silva, R.S.; Eguiluz, K.I.B.; Salazar-Banda, G.R. Enhanced stability and electrocatalytic properties of Ti/RuxIr1− xO2 anodes produced by a new laser process. Chem. Eng. J. 2019, 355, 439–447. [Google Scholar] [CrossRef]
  18. Wei, C.; Sun, S.; Mandler, D.; Wang, X.; Qiao, S.Z.; Xu, Z.J. Approaches for measuring the surface areas of metal oxide electrocatalysts for determining their intrinsic electrocatalytic activity. Chem. Soc. Rev. 2019, 48, 2518–2534. [Google Scholar] [CrossRef]
  19. Özdokur, K.V.; Koçak, C.; Eden, Z.; Demir, Ç.; Çirak, E.; Yavuz, E.; Çağlar, B. Gold-Nanoparticles-Decorated ZrO2-CuO Nanocomposites: Synthesis, Characterization and A Novel Platform for Electrocatalytic Formaldehyde Oxidation. Chemistryselect 2022, 7, e202201411. [Google Scholar]
  20. Lin, F.; Dagle, V.; Winkelman, A.; Engelhard, M.; Kovarik, L.; Wang, Y.; Wang, Y.; Dagle, R.; Wang, H. Understanding the Deactivation of Ag− ZrO2/SiO2 Catalysts for the Single-step Conversion of Ethanol to Butenes. ChemCatChem 2021, 13, 999–1008. [Google Scholar] [CrossRef]
  21. Lee, T.K.; Andersson, R.; Dzulkurnain, N.A.; Hernández, G.; Mindemark, J.; Brandell, D. Polyester-ZrO2 Nanocomposite Electrolytes with High Li Transference Numbers for Ambient Temperature All-Solid-State Lithium Batteries. Batter. Supercaps 2021, 4, 653–662. [Google Scholar]
  22. Aguilar-Vallejo, A.; Álvarez-Contreras, L.; Guerra-Balcázar, M.; Ledesma-García, J.; Arriaga, L.G.; Arjona, N.; Rivas, S.V. Electrocatalytic Evaluation of Highly Stable Pt/ZrO2 Electrocatalysts for the Methanol Oxidation Reaction Synthesized Without the Assistance of Any Carbon Support. Chemelectrochem 2019, 6, 2107–2118. [Google Scholar] [CrossRef]
  23. Zahra, T.; Ahmad, K.; Zequine, C.; Gupta, R.; Malik, M.; Niazi, J.; Qureshi, A. Bio-inspired NiO/ZrO2 mixed oxides (NZMO) for oxygen evolution reactions: From facile synthesis to electrochemical analysis. J. Chem. Technol. Biotechnol. 2022, 98, 296–305. [Google Scholar] [CrossRef]
  24. Askari, N.; Baghizadeh, A.; Beheshti-Marnani, A.; Askari, M.; Di Bartolomeo, A. NiO–Co3O4–rGO as a Multicomponent Transition Metal Oxide Nanocatalyst for Ultra-level Detection of Nitrite in Beef and Tap Water Samples. Adv. Mater. Interfaces 2022, 9, 2201180. [Google Scholar]
  25. Askari, M.; Salarizadeh, P.; Beheshti-Marnani, A.; Di Bartolomeo, A. NiO-Co3O4-rGO as an efficient electrode material for supercapacitors and direct alcoholic fuel cells. Adv. Mater. Interfaces 2021, 8, 2100149. [Google Scholar] [CrossRef]
  26. Nodehi, A.; Atashi, H.; Mansouri, M. Improved photocatalytic degradation of reactive blue 81 using NiO-doped ZnO–ZrO2 nanoparticles. J. Dispers. Sci. Technol. 2019, 40, 766–776. [Google Scholar] [CrossRef]
  27. Li, H.; Wu, Y.; Li, C.; Gong, Y.; Niu, L.; Liu, X.; Jiang, Q.; Sun, C.; Xu, S. Design of Pt/t-ZrO2/g-C3N4 efficient photocatalyst for the hydrogen evolution reaction. Appl. Catal. B Environ. 2019, 251, 305–312. [Google Scholar]
  28. Yang, B.C.; Go, D.; Oh, S.; Shin, J.W.; Kim, H.J.; An, J. Atomic-layer-deposited ZrO2-doped CeO2 thin film for facilitating oxygen reduction reaction in solid oxide fuel cell. Appl. Surf. Sci. 2019, 473, 102–106. [Google Scholar]
  29. Lu, X.; Zhang, H.; Najafi, M. Possibility of NiO, ZrO2, ZnO and GrO2 Attached to Silicon and Carbon Nanostructures as Anode of Battery: Computational Examination. Silicon 2020, 12, 2107–2110. [Google Scholar] [CrossRef]
  30. Wu, H.; Belharouak, I.; Abouimrane, A.; Sun, Y.-K.; Amine, K. Surface modification of LiNi0.5Mn1.5O4 by ZrP2O7 and ZrO2 for lithium-ion batteries. J. Power Source 2010, 195, 2909–2913. [Google Scholar] [CrossRef]
  31. Pang, Z.; Duan, J.; Zhao, Y.; Tang, Q.; He, B.; Yu, L. A ceramic NiO/ZrO2 separator for high-temperature supercapacitor up to 140 °C. J. Power Source 2018, 400, 126–134. [Google Scholar]
  32. Sinha, S.; Singh, W.I.; Nongthombam, S.; Devi, N.A.; Laha, S.; Swain, B.S.; Swain, B.P. Optical properties, electrochemical analysis and corrosion resistance studies of polyaniline/reduced graphene Oxide/ZrO2 for supercapacitor application. J. Phys. Chem. Solids 2022, 161, 110478. [Google Scholar]
  33. Feng, Q.; Wang, M.; Han, X.; Chen, Q.; Dou, B.; Wang, P. Construction of an electrochemical biosensing platform based on hierarchical mesoporous NiO@ N-doped C microspheres coupled with catalytic hairpin assembly. ACS Appl. Bio Mater. 2020, 3, 1276–1282. [Google Scholar] [PubMed]
  34. Halley, S.; Ramaiyan, K.; Tsui, L.-K.; Garzon, F. A Review of Zirconia Oxygen, NOx, and Mixed Potential Gas Sensors-History and Current Trends. Sens. Actuators B Chem. 2022, 370, 132363. [Google Scholar] [CrossRef]
  35. Xavier, J.R. Electrochemical and mechanical investigation of newly synthesized NiO-ZrO2 nanoparticle–grafted polyurethane nanocomposite coating on mild steel in chloride media. J. Mater. Eng. Perform. 2021, 30, 1554–1566. [Google Scholar]
  36. Yin, M.; Zhang, L.; Wei, X.; Sun, Y.; Qi, S.; Chen, Y.; Tian, X.; Qiu, J.; Xu, D. Spongy Co/Ni-Bio-MOF-based electrochemical aptasensor for detection of kanamycin based on coral-like ZrO2@ Au as an amplification platform. J. Electroanal. Chem. 2022, 920, 116647. [Google Scholar] [CrossRef]
  37. Goudarzi, M.R.; Bagherzadeh, M.; Fazilati, M.; Riahi, F.; Salavati, H.; Esfahani, S.S. Evaluation of antibacterial property of hydroxyapatite and zirconium oxide-modificated magnetic nanoparticles against Staphylococcus aureus and Escherichia coli. IET Nanobiotechnol. 2019, 13, 449–455. [Google Scholar] [CrossRef]
  38. Turki Jalil, A.; Hussain Dilfy, S.; Oudah Meza, S.; Aravindhan, S.; Kadhim, M.; MAljeboree, A. CuO/ZrO2 nanocomposites: Facile synthesis, characterization and photocatalytic degradation of tetracycline antibiotic. J. Nanostructures 2021, 11, 333–346. [Google Scholar]
  39. Zahra, T.; Ahmad, K.; Sharif, S. Sustainable remediation of toxic industrial pollutant via NiO/ZrO2/Mn3O4 biomimetic nano-photocatalysts. Int. J. Environ. Sci. Technol. 2022, 1–8. [Google Scholar] [CrossRef]
  40. Fatema, K.N.; Lim, C.-S.; Liu, Y.; Cho, K.-Y.; Jung, C.-H.; Oh, W.-C. 3D Modeling of Silver Doped ZrO2 Coupled Graphene-Based Mesoporous Silica Quaternary Nanocomposite for a Nonenzymatic Glucose Sensing Effects. Nanomaterials 2022, 12, 193. [Google Scholar]
  41. Hefnawy, M.; Fadlallah, S.; El-Sherif, R.; Medany, S. Synergistic effect of Cu-doped NiO for enhancing urea electrooxidation: Comparative electrochemical and DFT studies. J. Alloys Compd. 2022, 896, 162857. [Google Scholar]
  42. Askari, M.B.; Salarizadeh, P.; Seifi, M.; Rozati, S.M. Ni/NiO coated on multi-walled carbon nanotubes as a promising electrode for methanol electro-oxidation reaction in direct methanol fuel cell. Solid State Sci. 2019, 97, 106012. [Google Scholar]
  43. Dabirifar, Z.; Khadempir, S.; Kardan, A.; Karaman, C. Boosting the electrocatalytic activity of ZrO2/MWCNT supported PdPt bi-metallic electrocatalyst towards ethanol oxidation reaction by electrochemical activation process and modeling by artificial neural network approach. Chem. Eng. Res. Des. 2022, 180, 38–49. [Google Scholar] [CrossRef]
  44. Gwebu, S.; Maxakato, N. The influence of ZrO2 promoter in Pd/fCNDs-ZrO2 catalyst towards alcohol fuel electrooxidation in alkaline media. Mater. Res. Express 2020, 7, 015607. [Google Scholar]
  45. Luo, Y.; Zhong, W.; Huang, P.; Ou, H.; Fu, H.; Liu, C.; Xiao, Z.; Xu, S. Improved electrocatalytic activity of Pt catalyst supported on core–shell CMs@ NiO for methanol oxidation. New J. Chem. 2021, 45, 12879–12885. [Google Scholar]
  46. Rezaee, S.; Shahrokhian, S. Facile synthesis of petal-like NiCo/NiO-CoO/nanoporous carbon composite based on mixed-metallic MOFs and their application for electrocatalytic oxidation of methanol. Appl. Catal. B Environ. 2019, 244, 802–813. [Google Scholar] [CrossRef]
  47. Sheikhi, S.; Jalali, F. Remarkable electrocatalytic activity of Ni-nanoparticles on MOF-derived ZrO2-porous carbon/reduced graphene oxide towards methanol oxidation. Int. J. Hydrogen Energy 2021, 46, 10723–10738. [Google Scholar] [CrossRef]
  48. Wang, H.; Yang, Y.; Ren, Y.; Chen, D.; Wei, J.; Wang, L.; Xie, A.; Luo, S. Electrochemical synthesis of Pt nanoparticles on ZrO2/MWCNTs hybrid with high electrocatalytic performance for methanol oxidation. J. Electroanal. Chem. 2021, 898, 115641. [Google Scholar]
  49. Zhang, D.; Zhang, J.; Wang, H.; Cui, C.; Jiao, W.; Gao, J.; Liu, Y. Novel Ni foam based nickel oxalate derived porous NiO nanostructures as highly efficient electrodes for the electrooxidation of methanol/ethanol and urea. J. Alloys Compd. 2019, 806, 1419–1429. [Google Scholar]
  50. Tang, X.; Yang, Q. Enhanced Electrochemical Performance of NiO Nanoflakes Assembled on ZnCl2-Activated Carbonized Filter Paper. J. Electron. Mater. 2019, 48, 7336–7344. [Google Scholar] [CrossRef]
  51. Sadroddini, M.; Razzaghi-Kashani, M. Silica-decorated reduced graphene oxide (SiO2@rGO) as hybrid fillers for enhanced dielectric and actuation behavior of polydimethylsiloxane composites. Smart Mater. Struct. 2019, 29, 015028. [Google Scholar] [CrossRef]
  52. Askari, M.B.; Rozati, S.M.; Salarizadeh, P.; Saeidfirozeh, H.; Di Bartolomeo, A. A remarkable three-component RuO2-MnCo2O4/rGO nanocatalyst towards methanol electrooxidation. Int. J. Hydrogen Energy 2021, 46, 36792–36800. [Google Scholar] [CrossRef]
  53. Askari, M.B.; Rozati, S.M. Construction of Co3O4-Ni3S4-rGO ternary hybrid as an efficient nanoelectrocatalyst for methanol and ethanol oxidation in alkaline media. J. Alloys Compd. 2022, 900, 163408. [Google Scholar] [CrossRef]
  54. Jinxi, W.; Aimin, W.; Ghasemi, A.K.; Lashkenari, M.S.; Pashai, E.; Karaman, C.; Niculina, D.E.; Karimi-Maleh, H. Tailoring of ZnFe2O4-ZrO2-based nanoarchitectures catalyst for supercapacitor electrode material and methanol oxidation reaction. Fuel 2023, 334, 126685. [Google Scholar] [CrossRef]
  55. Sheikhi, S.; Jalali, F. Zr-MOF@Polyaniline as an efficient platform for nickel deposition: Application to methanol electro-oxidation. Fuel 2021, 296, 120677. [Google Scholar] [CrossRef]
  56. Wang, F.; Qiao, J.; Wang, J.; Wu, H.; Yue, X.; Wang, Z.; Sun, W.; Sun, K. Reduced graphene oxide supported Ni@Au@Pd core@bishell nanoparticles as highly active electrocatalysts for ethanol oxidation reactions and alkaline direct bioethanol fuel cells applications. Electrochimica Acta 2018, 271, 1–9. [Google Scholar] [CrossRef]
  57. Mahmood, K.; Mansoor, M.A.; Iqbal, M.; Kalam, A.; Iqbal, J.; Jilani, A.; Wageh, S. An Electrochemical Investigation of Methanol Oxidation on Thin Films of Nickel Oxide and Its Composites with Zirconium and Yttrium Oxides. Crystals 2022, 12, 534. [Google Scholar] [CrossRef]
  58. Zhou, W.Q.; Xi, B.J.; Chang, X.W.; Wang, B.; Wu, X.Q.; Li, S.; Wu, Y.P.; Li, D.S. Facile in Situ Transformation of NiOOH into MOF-74 (Ni)/NiO OH Heterogeneous Composite for Enchancing Electrocatalytic Methanol Oxidation. Molecules 2022, 27, 2113. [Google Scholar] [CrossRef]
  59. Askari, N.; Askari, M.B.; Di Bartolomeo, A. Electrochemical Alcohol Oxidation and Biological Properties of Mn3O4-Co3O4-rGO. J. Electrochem. Soc. 2022, 169, 106511. [Google Scholar] [CrossRef]
  60. Askari, M.B.; Azizi, S.; Moghadam, M.T.T.; Seifi, M.; Rozati, S.M.; Di Bartolomeo, A. MnCo2O4/NiCo2O4/rGO as a Catalyst Based on Binary Transition Metal Oxide for the Methanol Oxidation Reaction. Nanomaterials 2022, 12, 4072. [Google Scholar] [CrossRef]
  61. Sun, H.; Huang, H.; Hu, C.; Yan, Y.; Hu, Y.; Liu, S.J.; Wen, H.R. Synthesis of Au-NiOx/ultrathin graphitic C3N4 nanocomposite for electrochemical non-platinum oxidation of methanol. Int. J. Hydrogen Energy 2022, 47, 22796–22805. [Google Scholar] [CrossRef]
  62. Shojaeifar, M.; Askari, M.B.; Hashemi, S.R.S.; Di Bartolomeo, A. MnO2-NiO-MWCNTs nanocomposite as a catalyst for methanol and ethanol electrooxidation. J. Phys. D Appl. Phys. 2022, 55, 355502. [Google Scholar] [CrossRef]
  63. Eshghi, A.; Behbahani, E.S.; Kheirmand, M.; Ghaedi, M. Pd, Pd–Ni and Pd–Ni–Fe nanoparticles anchored on MnO2/Vulcan as efficient ethanol electro-oxidation anode catalysts. Int. J. Hydrogen Energy 2018, 44, 28194–28205. [Google Scholar] [CrossRef]
Nanomaterials 13 00679 g001 550
Figure 1. XRD pattern of ZrO2/NiO (dark curve) and ZrO2/NiO/rGO (red curve).
Figure 1. XRD pattern of ZrO2/NiO (dark curve) and ZrO2/NiO/rGO (red curve).
Nanomaterials 13 00679 g001
Nanomaterials 13 00679 g002 550
Figure 2. SEM images of ZrO2/NiO (a–c) and ZrO2/NiO/rGO (d–f). BF-TEM images and the element mapping patterns of ZrO2/NiO (g).
Figure 2. SEM images of ZrO2/NiO (a–c) and ZrO2/NiO/rGO (d–f). BF-TEM images and the element mapping patterns of ZrO2/NiO (g).
Nanomaterials 13 00679 g002
Nanomaterials 13 00679 g003 550
Figure 3. CV curves (a) and EIS plots (b) of ZrO2/NiO and ZrO2/NiO/rGO in 0.5 M KOH. CV curves of ZrO2/NiO and ZrO2/NiO/rGO in 0.5 M KOH/0.1 M methanol (c) and 0.5 M KOH/0.1 M ethanol (d).
Figure 3. CV curves (a) and EIS plots (b) of ZrO2/NiO and ZrO2/NiO/rGO in 0.5 M KOH. CV curves of ZrO2/NiO and ZrO2/NiO/rGO in 0.5 M KOH/0.1 M methanol (c) and 0.5 M KOH/0.1 M ethanol (d).
Nanomaterials 13 00679 g003
Nanomaterials 13 00679 g004 550
Figure 4. CV from ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in 0.5 M KOH/different concentrations of methanol. CV from ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in 0.5 M KOH/different concentrations of ethanol.
Figure 4. CV from ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in 0.5 M KOH/different concentrations of methanol. CV from ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in 0.5 M KOH/different concentrations of ethanol.
Nanomaterials 13 00679 g004
Nanomaterials 13 00679 g005 550
Figure 5. CV from ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in 0.5 M KOH/0.7 M methanol/different scan rates. CV from ZrO2/NiO (d) and ZrO2/NiO/rGO (e) in 0.5 M KOH/0.5 M ethanol/different scan rates. The plot of the square root of scan rate in terms of maximum current density for ZrO2/NiO and ZrO2/NiO/rGO in MOR (c) and in EOR (f).
Figure 5. CV from ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in 0.5 M KOH/0.7 M methanol/different scan rates. CV from ZrO2/NiO (d) and ZrO2/NiO/rGO (e) in 0.5 M KOH/0.5 M ethanol/different scan rates. The plot of the square root of scan rate in terms of maximum current density for ZrO2/NiO and ZrO2/NiO/rGO in MOR (c) and in EOR (f).
Nanomaterials 13 00679 g005
Nanomaterials 13 00679 g006 550
Figure 6. Cyclic stability for ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in MOR and cyclic stability for ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in EOR.
Figure 6. Cyclic stability for ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in MOR and cyclic stability for ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in EOR.
Nanomaterials 13 00679 g006
Nanomaterials 13 00679 g007 550
Figure 7. LSV curves of ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in MOR process and LSV of ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in EOR process at different temperatures.
Figure 7. LSV curves of ZrO2/NiO (a) and ZrO2/NiO/rGO (b) in MOR process and LSV of ZrO2/NiO (c) and ZrO2/NiO/rGO (d) in EOR process at different temperatures.
Nanomaterials 13 00679 g007
Table
Table 1. Comparison of MOR and EOR performances of ZrO2/NiO/rGO nanocatalyst with other research.
Table 1. Comparison of MOR and EOR performances of ZrO2/NiO/rGO nanocatalyst with other research.
ElectrocatalystElectrolyte CompositionPeak Potential (V)Current Density (mA cm–2)Scan Rate (mV/s)Reference
ZrO2/NiO/rGO0.7 M Methanol/0.5 M KOH0.5226.620This work
ZrO2/NiO/rGO0.5 M Ethanol/0.5 M KOH0.5217.320This work
ZnFe2O4-ZrO2/Pt1 M Methanol/0.5 M KOH0.35104.7550[54]
Zr-MOF@PANI/Ni-NPs/GCE0.5 M Methanol/1 M NaOH0.75291.6100[55]
Ni@Au@Pd/rGO1 M Ethanol/2 M KOH0.68.8550[56]
NiO-Y2O3/FTO0.6 M Methanol/0.5 M NaOH0.656.2100[57]
NiO-ZrO2/FTO0.6 M Methanol/0.5 M NaOH0.6510100[57]
MOF-74(Ni)/NiOOH1 M Methanol/1 M KOH0.627.6250[58]
Mn3O4-CeO2-rGO0.8 M Methanol/1 M KOH0.5117.790[5]
Mn3O4-Co3O4-rGO1 M Methanol/1 M KOH0.4816.5100[59]
Mn3O4-Co3O4-rGO0.7 M Eethanol/1 M KOH0.555.760[59]
MnCo2O4/NiCo2O4/rGO2 M Methanol/2 M KOH0.5824.7620[60]
Au-NiOx/g-C3N40.5 M Methanol/1 M KOH0.3532.5Not Reported[61]
MnO2–NiO–MWCNTs0.5 M EtOH/1 M KOH0.55148 μA/cm250[62]
Pd–Ni–Fe/MnO2/Vulcan 1 M Ethanol/0.2 M KOH+0.05–+0.33.03100[63]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Askari, M.B.; Beitollahi, H.; Di Bartolomeo, A. Methanol and Ethanol Electrooxidation on ZrO2/NiO/rGO. Nanomaterials 2023, 13, 679. https://doi.org/10.3390/nano13040679

AMA Style

Askari MB, Beitollahi H, Di Bartolomeo A. Methanol and Ethanol Electrooxidation on ZrO2/NiO/rGO. Nanomaterials. 2023; 13(4):679. https://doi.org/10.3390/nano13040679

Chicago/Turabian Style

Askari, Mohammad Bagher, Hadi Beitollahi, and Antonio Di Bartolomeo. 2023. "Methanol and Ethanol Electrooxidation on ZrO2/NiO/rGO" Nanomaterials 13, no. 4: 679. https://doi.org/10.3390/nano13040679

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop