Editorial

2 pages, 176 KiB

Open AccessEditorial

Innovative Electrocatalysts for Fuel Cell and Battery Applications

by Carmelo Lo Vecchio

Catalysts 2023, 13(2), 359; https://doi.org/10.3390/catal13020359 - 06 Feb 2023

Viewed by 754

The development of sustainable energy systems is essential to hinder global warming and environmental pollution emergencies [...] Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

Research

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11 pages, 2856 KiB

Open AccessFeature PaperArticle

Water Splitting with Enhanced Efficiency Using a Nickel-Based Co-Catalyst at a Cupric Oxide Photocathode

by Carmelo Lo Vecchio, Stefano Trocino, Giosuè Giacoppo, Orazio Barbera, Vincenzo Baglio, María I. Díez-García, Maxime Contreras, Roberto Gómez and Antonino Salvatore Aricò

Catalysts 2021, 11(11), 1363; https://doi.org/10.3390/catal11111363 - 12 Nov 2021

Cited by 7 | Viewed by 1838

Abstract

Homemade non-critical raw materials such as Ni or NiCu co-catalysts were added at the photocathode of a tandem cell, constituted by photoelectrodes made of earth-abundant materials, to generate green solar hydrogen from photoelectrochemical water splitting. Oxygen evolving at the Ti-and-P-doped hematite/TCO-based photoanode and [...] Read more.

Homemade non-critical raw materials such as Ni or NiCu co-catalysts were added at the photocathode of a tandem cell, constituted by photoelectrodes made of earth-abundant materials, to generate green solar hydrogen from photoelectrochemical water splitting. Oxygen evolving at the Ti-and-P-doped hematite/TCO-based photoanode and hydrogen at the cupric oxide/GDL-based photocathode are separated by an anion exchange polymer electrolyte membrane placed between them. The effect of the aforementioned co-catalysts was studied in a complete PEC cell in the presence of the ionomer dispersion and the anionic membrane to evaluate their impact under practical conditions. Notably, different amounts of Ni or NiCu co-catalysts were used to improve the hydrogen evolution reaction (HER) kinetics and the overall solar-to-hydrogen (STH) efficiency of the photoelectrochemical cells. At −0.6 V, in the bias-assisted region, the photocurrent density reaches about 2 mA cm⁻² for a cell with 12 µg cm⁻² of Ni loading, followed by 1.75 mA cm⁻² for the cell configuration based on 8 µg cm⁻² of NiCu. For the best-performing cell, enthalpy efficiency at −0.4 V reaches a first maximum value of 2.03%. In contrast, the throughput efficiency, which is a ratio between the power output and the total power input (solar + electric) provided by an external source, calculated at −1.225 V, reaches a maximum of 10.75%. This value is approximately three times higher than the best results obtained in our previous studies without the use of co-catalysts at the photocathode. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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13 pages, 2245 KiB

Open AccessFeature PaperArticle

Ionic Liquid-Derived Carbon-Supported Metal Electrocatalysts as Anodes in Direct Borohydride-Peroxide Fuel Cells

by Jadranka Milikić, Raisa C. P. Oliveira, Andres Tapia, Diogo M. F. Santos, Nikola Zdolšek, Tatjana Trtić-Petrović, Milan Vraneš and Biljana Šljukić

Catalysts 2021, 11(5), 632; https://doi.org/10.3390/catal11050632 - 14 May 2021

Cited by 3 | Viewed by 2310

Abstract

Three different carbon-supported metal (gold, platinum, nickel) nanoparticle (M/c-IL) electrocatalysts are prepared by template-free carbonization of the corresponding ionic liquids, namely [Hmim][AuCl₄], [Hmim]₂[PtCl₄], and [C₁₆mim]₂[NiCl₄], as confirmed by X-ray diffraction analysis, [...] Read more.

Three different carbon-supported metal (gold, platinum, nickel) nanoparticle (M/c-IL) electrocatalysts are prepared by template-free carbonization of the corresponding ionic liquids, namely [Hmim][AuCl₄], [Hmim]₂[PtCl₄], and [C₁₆mim]₂[NiCl₄], as confirmed by X-ray diffraction analysis, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and Raman spectroscopy. The electrochemical investigation of borohydride oxidation reaction (BOR) at the three electrocatalysts by cyclic voltammetry reveals different behavior for each material. BOR is found to be a first-order reaction at the three electrocatalysts, with an apparent activation energy of 10.6 and 13.8 kJ mol⁻¹ for Pt/c-IL and Au/c-IL electrocatalysts, respectively. A number of exchanged electrons of 5.0, 2.4, and 2.0 is obtained for BOR at Pt/c-IL, Au/c-IL, and Ni/c-IL electrodes, respectively. Direct borohydride-peroxide fuel cell (DBPFC) tests done at temperatures in the 25–65 °C range show ca. four times higher power density when using a Pt/c-IL anode than with an Au/c-IL anode. Peak power densities of 40.6 and 120.5 mW cm⁻² are achieved at 25 and 65 °C, respectively, for DBPFC with a Pt/c-IL anode electrocatalyst. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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14 pages, 1801 KiB

Open AccessArticle

Membrane-Less Ethanol Electrooxidation over Pd-M (M: Sn, Mo and Re) Bimetallic Catalysts

by Estela Ruiz-López, Manuel Antonio Diaz-Perez, Antonio de Lucas-Consuegra, Fernando Dorado and Juan Carlos Serrano-Ruiz

Catalysts 2021, 11(5), 541; https://doi.org/10.3390/catal11050541 - 23 Apr 2021

Cited by 3 | Viewed by 1939

Abstract

The effect of the addition of three oxophilic co-metals (Sn, Mo and Re) on the electrochemical performance of Pd in the ethanol oxidation reaction (EOR) was investigated by performing half-cell and membrane-less electrolysis cell experiments. While the additions of Sn and Re were [...] Read more.

The effect of the addition of three oxophilic co-metals (Sn, Mo and Re) on the electrochemical performance of Pd in the ethanol oxidation reaction (EOR) was investigated by performing half-cell and membrane-less electrolysis cell experiments. While the additions of Sn and Re were found to improve significantly the EOR performance of Pd, Mo produced no significant promotional effect. When added in significant amounts (50:50 ratio), Sn and Re produced a 3–4 fold increase in the mass-normalized oxidation peak current as compared to the monometallic Pd/C material. Both the electrochemical surface area and the onset potential also improved upon addition of Sn and Re, although this effect was more evident for Sn. Cyclic voltammetry (CV) measurements revealed a higher ability of Sn for accommodating OH- species as compared to Re, which could explain these results. Additional tests were carried out in a membrane-less electrolysis system. Pd₅₀Re₅₀/C and Pd₅₀Sn₅₀/C both showed higher activity than Pd/C in this system. Chronopotentiometric measurements at constant current were carried out to test the stability of both catalysts in the absence of a membrane. Pd₅₀Sn₅₀/C was significantly more stable than Pd₅₀Re₅₀/C, which showed a rapid increase in the potential with time. Despite operating in the absence of a membrane, both catalysts generated a high-purity (e.g., 99.99%) hydrogen stream at high intensities and low voltages. These conditions could lead to significant energy consumption savings compared to commercial water electrolyzers. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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23 pages, 4341 KiB

Open AccessFeature PaperArticle

Clarifying the Role of the Reducers-to-Oxidizers Ratio in the Solution Combustion Synthesis of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ Oxygen Electrocatalysts

by Francesca Deganello, Leonarda F. Liotta, Chiara Aliotta, Antonio Barbucci, Massimo Viviani, Davide Clematis, Maria Paola Carpanese and Sabrina Presto

Catalysts 2020, 10(12), 1465; https://doi.org/10.3390/catal10121465 - 15 Dec 2020

Cited by 1 | Viewed by 2280

Abstract

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ perovskite-type compounds are well-known mixed ionic-electronic conductors for oxygen electrocatalytic applications, although their performance is strictly dependent on the selected preparation methodology and processing parameters. The reducers-to-oxidizers ratio (Φ) is a very important [...] Read more.

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ perovskite-type compounds are well-known mixed ionic-electronic conductors for oxygen electrocatalytic applications, although their performance is strictly dependent on the selected preparation methodology and processing parameters. The reducers-to-oxidizers ratio (Φ) is a very important parameter in the solution combustion synthesis of mixed ionic-electronic conductors. Selection of Φ is not trivial and it strongly depends on the type of fuel used, the chemical composition and the specific application of the material. This work clarifies the role of Φ in the solution combustion synthesis of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ for application as oxygen electrocatalysts. Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ powders were synthesized by solution combustion synthesis using sucrose-polyethylene glycol fuel mixtures with reducers-to-oxidizers ratio values between 1 (stoichiometric) and 3 (over-stoichiometric). Chemical-physical properties were studied by X-ray diffraction, scanning electron microscopy, N₂ adsorption at −196 °C, H₂-temperature programmed reduction and thermogravimetric analysis. The results evidenced the direct role of Φ on the intensity and redox environment of the combustion process, and its indirect influence on the Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ electrode materials properties. Taking into account the general picture, the highly over-stoichiometric Φ was selected as the optimal one and the electrochemical activity of the corresponding powder was tested by electrochemical impedance spectroscopy on electrolyte-supported half-cells employing a Ce_0.8Sm_0.2O_2-x electrolyte. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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20 pages, 8156 KiB

Open AccessArticle

NiPd Supported on Mesostructured Silica Nanoparticle as Efficient Anode Electrocatalyst for Methanol Electrooxidation in Alkaline Media

by Muliani Mansor, Sharifah Najiha Timmiati, Wai Yin Wong, Azran Mohd Zainoodin, Kean Long Lim and Siti Kartom Kamarudin

Catalysts 2020, 10(11), 1235; https://doi.org/10.3390/catal10111235 - 25 Oct 2020

Cited by 10 | Viewed by 2597

Abstract

The direct methanol fuel cell (DMFC) is a portable device and has the potential to produce 10 times higher energy density than lithium-ion rechargeable batteries. It is essential to build efficient methanol electrooxidation reaction electrocatalysts for DMFCs to achieve their practical application in [...] Read more.

The direct methanol fuel cell (DMFC) is a portable device and has the potential to produce 10 times higher energy density than lithium-ion rechargeable batteries. It is essential to build efficient methanol electrooxidation reaction electrocatalysts for DMFCs to achieve their practical application in future energy storage and conversion. A catalyst consisting of nickel–palladium supported onto mesostructured silica nanoparticles (NiPd–MSN) was synthesized by the wet impregnation method, while MSN was synthesized using the sol-gel method. MSN act as a catalyst support and has very good characteristics for practical support due to its large surface area (>1000 m²/g) and good chemical and mechanical stability. The microstructure and catalytic activity of the electrocatalysts were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), Brunauer–Emmet–Teller (BET) theory, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and chronoamperometry (CA). XRD showed that the NiPd–MSN electrocatalysts had a high crystallinity of PdO and NiO, while FESEM displayed that NiPd was dispersed homogeneously onto the high surface area of MSN. In alkaline media, the catalytic activity toward the methanol oxidation reaction (MOR) of NiPd–MSN demonstrated the highest, which was 657.03 mA mg⁻¹ more than the other electrocatalysts. After 3600 s of CA analysis at −0.2 V (vs. Ag/AgCl), the MOR mass activity of NiPd–MSN in alkaline media was retained at a higher mass activity of 190.8 mA mg⁻¹ while the other electrocatalyst was significantly lower than that. This electrocatalyst is a promising anode material toward MOR in alkaline media. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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Review

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20 pages, 2685 KiB

Open AccessReview

Recent Advances in the Electroreduction of CO₂ over Heteroatom-Doped Carbon Materials

by Ana Cristina Pérez-Sequera, Manuel Antonio Díaz-Pérez and Juan Carlos Serrano-Ruiz

Catalysts 2020, 10(10), 1179; https://doi.org/10.3390/catal10101179 - 14 Oct 2020

Cited by 23 | Viewed by 3377

Abstract

Ever-growing anthropogenic activity has increased global energy demands, resulting in growing concentrations of greenhouse gases such as CO₂ in the atmosphere. The electroreduction of CO₂ has been proposed as a potential solution for reducing anthropogenic CO₂ emissions. Despite the promising [...] Read more.

Ever-growing anthropogenic activity has increased global energy demands, resulting in growing concentrations of greenhouse gases such as CO₂ in the atmosphere. The electroreduction of CO₂ has been proposed as a potential solution for reducing anthropogenic CO₂ emissions. Despite the promising results obtained so far, some limitations hinder large-scale applications, especially those associated with the activity and selectivity of electrocatalysts. A good number of metal catalysts have been studied to overcome this limitation, but the high cost and low earth abundance of some of these materials are important barriers. In this sense, carbon materials doped with heteroatoms such as N, B, S, and F have been proposed as cheaper and widely available alternatives to metal catalysts. This review summarizes the latest advances in the utilization of carbon-doped materials for the electroreduction of CO₂, with a particular emphasis on the synthesis procedures and the electrochemical performance of the resulting materials. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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41 pages, 24586 KiB

Open AccessReview

Recent Studies on Multifunctional Electrocatalysts for Fuel Cell by Various Nanomaterials

by Sanha Jang, Kyeongmin Moon, Youchang Park, Sujung Park and Kang Hyun Park

Catalysts 2020, 10(6), 621; https://doi.org/10.3390/catal10060621 - 03 Jun 2020

Cited by 4 | Viewed by 4495

Abstract

Based on nanotechnology, nanocomposites are synthesized using nanoparticles (NP), which have some advantages in terms of multifunctional, economic, and environmental factors. In this review, we discuss the inorganic applications as well as catalytic applications of NPs. Recently, structural defects, heteroatomic doping, and heterostructures [...] Read more.

Based on nanotechnology, nanocomposites are synthesized using nanoparticles (NP), which have some advantages in terms of multifunctional, economic, and environmental factors. In this review, we discuss the inorganic applications as well as catalytic applications of NPs. Recently, structural defects, heteroatomic doping, and heterostructures of such efficient ideal catalysts and their application as multifunctional catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. It has been verified that the catalysts used in oxygen reduction reaction and OER can be used effectively in metal/air batteries. Moreover, it has been reported that high-efficiency catalysts are required to implement urea oxidation reaction (UOR), which involves a six-electron reaction, as an electrochemical reaction. We expect that this review can be applied to sustainable and diverse electrochemistry fields. Full article

(This article belongs to the Special Issue Innovative Electrocatalysts for Fuel Cell and Battery Applications)

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