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Article

Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis

by
Wenwen Wang
†,
Xinyi Bai
†,
Xiaochu Yuan
,
Yumin Liu
*,
Lin Yang
* and
Fangfang Chang
*
Collaborative Innovation Centre of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Materials 2023, 16(2), 840; https://doi.org/10.3390/ma16020840
Received: 12 December 2022 / Revised: 2 January 2023 / Accepted: 12 January 2023 / Published: 15 January 2023
(This article belongs to the Special Issue Alloys and Composites: Structural and Functional Applications)
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Abstract

:
The compositions and surface facets of platinum (Pt)-based electrocatalysts are of great significance for the development of direct alcohol fuel cells (DAFCs). We reported an approach for preparing ultrathin PtnCo100−n nanowire (NW) catalysts with high activity. The PtnCo100−n NW alloy catalysts synthesized by single-phase surfactant-free synthesis have adjustable compositions and (111) plane and strain lattices. X-ray diffraction (XRD) results indicate that the alloy composition can adjust the lattice shrinkage or expansion of PtnCo100−n NWs. X-ray photoelectron spectroscopy (XPS) results show that the electron structure of Pt is changed by the alloying effect caused by electron modulation in the d band, and the chemical adsorption strength of Pt is decreased, thus the catalytic activity of Pt is increased. The experimental results show that the activity of PtnCo100−n for the oxidation of methanol and ethanol is related to the exposed crystal surface, strain lattice and composition of catalysts. The PtnCo100−n NWs exhibit stronger electrocatalytic performance for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The dominant (111) plane Pt53Co47 exhibits the highest electrocatalytic activity in MOR, which is supported by the results of XPS. This discovery provides a new pathway to design high activity, stability nanocatalysts to enhance direct alcohol fuel cells.

1. Introduction

Direct alcohol fuel cells are gaining increased attention owing to advantages such as good durability, high energy conversion efficiency, clean and low temperature operation, environmental protection and sustainable regeneration [1,2]. Pt is the best catalyst for fuel cells and determines the properties of a fuel cell to a large extent, and is also an effective catalyst for the EOR and MOR. Huang’s team found that synthetic Pt catalyst showed very interesting dimension-dependent activity against ORR and MOR [3]. The conventional catalyst for MOR is Pt because of its excellent performance in selectivity and activity [4]; however, the use of Pt is restricted due to its high price and surface poisoning. Additionally, conserving expensive Pt catalysts is essential to advance their scalable usage in a sustainable energy economy. Pt-based catalysts are in a stage of rapid development, and the introduction of non-precious metals is notable for increasing the performance of Pt and reducing the amount of Pt required. Pt was alloyed with first-row transition metals [5,6,7,8], which is an acceptable method to solve the above-mentioned problems by virtue of the special electronic structure and geometric configuration [9,10]. One-dimensional (1D) nanostructured electrocatalysts, such as NWs, have been favored to solve the challenge with nanoparticles (NPs) [11,12,13,14]. Pt-based NWs possess significant activities [15]. CoPt nanowires have shown good performance in oxygen reduction [16,17] and methanol oxidation [18]. In addition, Pt NWs promote electron transfer during the reaction due to their larger accessible surface area [19]. Therefore, a clear pathway to enhance the performance of electrocatalysts is to develop Pt-M NWs with ultralong and ultrathin structures. PtnCo100−n NWs were prepared through a seed-mediated process in which superior nanostructures met the requirements for high density and exponential surfaces, showing better performance than NPs [20]. Using Co25Pt75 nanoparticles as catalyst, the highest reported current density is 47.1 mA cm−2 (Xia et al. [21]). For Co40Pt60 alloys used as catalysts in the shape of nanowires, the highest reported current density is 14 mA/cm2 (Bertin et al. [22]), while using Co23Pt77 NWs as catalyst, the highest MOR activity reported by Serrà et al. [23] is 7 mA cm−2.
In this work, we used a straightforward one-step hydrothermal technique to prepare PtnCo100−n NWs with tunable compositions, highly active facets, and lattice strain. We firstly found that the electrocatalytic performance of ultrathin PtnCo100−n nanowires (NWs) (≈2.1 nm) is improved by regulating the compositions, high active facets and lattice strain of catalysts for alcohol oxidation. In mass activity (MA) and specific activity (SA), PtnCo100−n NW catalyst demonstrates higher MOR and EOR activity and stability in comparison to Pt/C. The structure and chemical makeup of the catalysts were examined using high-resolution transmission electron microscopy (HR-TEM) and XRD. The findings demonstrated that the catalyst compositions alter the lattice strain and dominating (111) facets of PtnCo100−n NWs with adjustable compositions. The improved activity and stability for MOR and EOR of ultrathin PtnCo100−n NWs reveals the relation among morphology, facets, lattice strain and bimetallic compositions. Additionally, the inclusion of Co alters the crystal structure, redesigning the electrical structure and considerably reducing the consumption of Pt.

2. Experimental Section

2.1. Chemicals

Ethanol, platinum (II) acetylacetonate (Pt(acac)2), oleylamine, cobalt (II) acetylacetonate (Co(acac)2), N, N-dimethylformamide (DMF), and 1-heptanol were bought from Aladdin. Hexane and KOH were obtained from Stem Chemicals. Potassium chloride and ethylene glycol (EG) were purchased from Deen reagent. All gases were purchased from Airgas.

2.2. Preparation of PtnCo100−n NWs

The PtnCo100−n catalysts were prepared using a one-step hydrothermal method. In this synthesis [24], KOH (1.0 g) was entirely dispersed in a solution including 5.0 mL 1-heptanol, 10 mL DMF, 20 mL oleylamine and 36 mL EG by magnetic stirring. Then, different atomic ratios of Pt(acac)2 precursors and Co(acac)2 precursors were dissolved in the above solution, stirred overnight, and subsequently transferred to an autoclave and kept at 180 ℃ for 8 h to obtain Pt70Co30 NWs. The ratio of Co(acac)2 and Pt(acac)2 precursors was adjusted to control compositions. The PtnCo100−n NWs were washed with ethanol and collected though centrifugation and dispersed in ethanol for further use.
The as-obtained PtnCo100−n NWs were loaded on Vulcan XC-72 (20 wt% metal loading) carbon to prepare PtnCo100−n/C for catalytic measurement. Vulcan XC-72 carbon was added into ethanol and stirred to form a uniform dispersion, and then the as-obtained PtnCo100−n NWs catalyst was added to the above dispersion and stirred to ensure the catalysts loaded on carbon, which was collected and dried to obtain the final catalyst. Pt NWs was synthesized in the same way without adding the Co(acac)2 precursor.

2.3. Characterizations

Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to analyze the elementary compositions and loading for catalysts [25]. Transmission electron microscope (200 kV) scanning performed on an FEI Titan G2 F20 microscope was used to investigate the morphology of the resulting catalysts [26]. XRD was conducted to analyze the structures of PtnCo100−n/C. The XPS technique was used to analyze the chemical state of the catalysts [27].

2.4. Electrochemical Measurements

The ink was created by dispersing 2.0 mg of catalysts using ultrasonication for 50 min in a solution including isopropanol, water, and 5 wt% Nafion (19:1:0.015, v/v/v). To form a uniformly thin film that served as the working electrode, the catalyst ink (10 μL) was pipetted onto a polished glassy carbon rotating disk electrode (0.196 cm2). On a CHI 760E electrochemical workstation, electrochemical tests were conducted in a three-electrode cell (CH Instrument, Inc., Bee Cave, TX, USA). By using cyclic voltammetry (CV) and rotating disk electrode (RDE) curves, the electrocatalytic activity of the PtnCo100−n/C was investigated. Before CV and RDE tests, the electrolyte was bubbled with pure N2 and O2, respectively, for more than 30 min to build a saturated testing environment. The properties of PtnCo100−n/C were assessed mainly by MA as well as SA.

3. Results and Discussion

3.1. NW Morphology

KOH, Pt(acac)2 and Co(acac)2 were added to synthesize PtnCo100−n nanoalloy catalysts in a mixture containing oleylamine DMF, 1-heptanol and EG, which was stirred overnight, transferred to an autoclave, and then kept at 180 ℃ to obtain the target product. 1-heptanol acted as a reducing agent of Co2+ to Co during the synthesis process. In terms of morphology and structure, TEM analysis showed that the as-obtained PtnCo100−n exhibited a bundle network structure, which was composed of multiple ultra-thin nanowires interwoven (Figure 1a–c). The diameter of each nanowire was about 0.21 nm, and the ultra-long nanowires were several micrometers in length with a high aspect ratio. The reason why PtnCo100−n NWs possess this special structure has two aspects. Firstly, the hydrophobic interaction of DMFs helps to minimize the free energy of PtnCo100−n synthesis, resulting in a strong cohesive interaction on the NWs. Secondly, there is a propensity to develop active defects along the NWs, which combine with the different NWs contacted to form the network structure [28]. Structural defects, such as grain boundaries and holes, can enhance catalytic activity. Figure 1 shows TEM images of PtnCo100−n NWs (Figure 1a–c) and HR-TEM observations (Figure 1d–f). The HR-TEM image shown in Figure 1 reveals the single crystal properties of each alloy nanowire. The lattice fringes of PtnCo100−n fell in between Pt and Co, which was gradually increased, indicating that Co atoms successfully integrated into the Pt nanostructure. As the proportion of platinum increased, the morphology of the NWs was gradually thinned and terminated by the (111) facet, which was reported in our previous work [29,30].
The structure of PtnCo100−n/C was characterized by XRD and XPS techniques. Figure 2a displays the XRD patterns of Pt27Co73/C, Pt53Co47/C, and Pt70Co30/C. The diffraction peaks of PtnCo100−n/C with different compositions were located between Pt (JCPDS No. 04-0802) and Co (JCPDS No. 15-0806), and were obviously exponential with face-centered cubic (fcc) PtCo alloy [31]. The peaks located at 40.37°, 39.87° and 39.82° corresponded to the (111) planes of Pt27Co73/C, Pt53Co47/C and Pt70Co30/C, respectively. The (111) diffraction peaks’ small downshift indicated a slight increase in Pt content in the NWs. The broad (111) peak, (200) peak and (220) peak indicated the formation of a nanoscale crystal structure. XRD data showed that the compositions of the nanoalloy catalysts for Pt27Co73/C, Pt53Co47/C and Pt70Co30/C were uniform, and there was no phase segregation in the samples. The diffraction peak of PtnCo100−n/C became sharp and showed a slight blue shift with the increase in Co%, proving that the smaller Co atoms entered into the NWs and might result in lattice strain. The lattice strain would influence the electrocatalytic properties through a possible geometric effect. As shown in Figure 2b, PtnCo100−n/C exhibited lattice expansion when the amount of Pt was less than 50%, and lattice shrinkage when Pt% was greater than 50%, conforming to Vegard’s law. XPS analysis was performed to understand the chemical states of Pt and Co as well as surface compositions of Pt and Co in PtnCo100−n/C. Figure 2c, d shows the Pt 4f and Co 2p XPS spectra, indicating that Co and Pt were in the metallic state. XPS analysis also confirmed the existence of Pt and Co in the as-obtained PtnCo100−n/C with different compositions. Figure 2c illustrates the Pt 4f XPS spectra for Pt27Co73/C, Pt57Co43/C and Pt70Co30/C. The peaks of Pt 4f7/2 appeared at 71.9, 71.9, and 72.2 eV, and the peaks of Pt 4f5/2 appeared at 75.1, 75.1 and 75.3 eV, respectively. The binding energy of Pt 4f showed an obviously blue shift relative to the XPS data for pure Pt, which suggested charge transfer from Pt to Co. The positive shift of the Pt binding energy suggested that the center of the d-band had shifted down.

3.2. Electrocatalytic Properties

The CV technique was used to study the MOR and EOR performance of the PtnCo100−n NWs/C as anodic catalysts. As shown in Figure 3, CVs were recorded in N2-saturated 0.1 M HClO4 + 0.5 M CH3OH/C2H5OH solution with a 50 mV s−1 scan speed. In MOR and EOR, the MA and SA were the foremost parameters. The Pt loading of the Pt27Co73/C, Pt53Co47/C, Pt70Co30/C, Pt/C, and commercial Pt were determined to be 35%, 25%, 30%, 30% and 20% by ICP-OES, respectively. We first evaluated the electrocatalytic performance of Pt/C and PtnCo100−n/C for MOR. The MOR performance of PtnCo100−n/C catalysts is shown in Figure 3a. The peak currents and peak potentials showed that the PtnCo100−n/C catalyst exhibited higher activity than the Pt/C catalyst. The Pt53Co47/C exhibited an MA of 2.15 A mg Pt−1, which was 1.38, 2.11, 3.58 and 4.78 times higher than those of Pt27Co73/C (1.56 A mg Pt−1), Pt70Co30/C (1.02 A mg Pt−1), Pt/C (0.60 A mg Pt−1), and commercial Pt/C (0.45 A mg Pt−1), respectively. The Pt27Co73/C exhibited the highest SA of 3.31 mA/cm2, which was 1.655, 2.98, 5.02 and 4.60 times higher than those of Pt53Co47/C (2.00 mA/cm2), Pt70Co30/C (1.11 mA/cm2), Pt/C (0.66 mA/cm2), and commercial Pt/C (0.72 mA/cm2), respectively (Figure 3b). Pt27Co73/C and Pt53Co47/C displayed higher activity for the MOR (Table 1) in comparison to the literature [32,33,34,35]. The EOR performance of commercial Pt/C and Pt nCo100−n/C catalysts is evaluated in Figure 3c,d. The PtnCo100−n/C catalyst exhibited higher activity than commercial Pt/C, as shown in Figure 3c. Figure 3d and Table 2 show that Pt27Co73/C exhibited the largest MA value (2.11 A mg−1) and largest SA (1.44 mA/cm2) of EOR, which was 3.91 times and 1.67 times that of Pt/C (0.54 A mg−1and 0.86 mA/cm2), respectively. Pt53Co47/C and Pt27Co73/C had higher activity for the EOR (Table 3) compared with the literature [36,37,38,39]. From the catalytic performance of MOR and EOR, it can be seen that the introduction of Co played an important part in the improvement of their performance. The If/Ib ratio can be used to certify the CO tolerance of catalysts [40]. The If/Ib ratio of Pt53Co47/C catalyst was 1.21, larger than that of Pt/C catalysts (1.05) (Figure 3a), due to facilitating the oxidation of methanol via relieving the CO poisoning with Co. The I f/I b ratio of the Pt27Co73/C catalyst was 1.14, larger than that of the Pt/C catalysts (0.83) (Figure 3c), which could be ascribed to its anti-poisoning enhancement in the presence of Co.
Figure 4a shows CVs of Pt27Co73/C, Pt57Co43/C, Pt70Co30/C and commercial Pt/C catalysts in 0.1 M HClO4 solution. As shown in Figure 4b, the electrochemical active surface area (ECSA) on behalf of the effective number of active catalytic sites, was determined from the H2 desorption peak areas of CV. The Pt27Co73/C, Pt57Co43/C, Pt70Co30/C and commercial Pt/C catalysts exhibited ECSA values of 30.6, 43.2, 54.9 and 49.9 m2g−1 Pt, respectively. The introduction of Co induced less exposure of the Pt active sites. However, the alloying with a higher atomic ratio of Co reduced the NW lengths and also led to an increase in the ECSA.

3.3. Durability

In practical applications, durability is also an important requirement for catalysts [41]. Hence, the initial stability of the PtnCo100−n/C was assessed by chronoamperometric (CA) tests. Through a comparison of PtnCo100−n/C catalyst with different components and commercial Pt/C, it was found that Pt53Co47/C and Pt27Co73/C have excellent catalytic activity. CA measurements of the catalysts were conducted at 0.65V (vs. SCE) in N2 -saturated 0.1 M HClO4 aqueous solution containing 0.5 M methanol/ethanol to evaluate their stability (Figure 4). CA curves indicated that the Pt27Co73/C catalyst and Pt53Co47/C electrocatalysts exhibited excellent stability. The Pt27Co73/C and Pt53Co47/C catalysts exhibited much higher initial current densities than Pt/C. The current density of Pt27Co73 C and Pt53Co47/C remaining were also much higher than that of Pt/C after 5000 s tests. There was about 22.1% and 21.8% activity retention of Pt53Co47 NWs/C and Pt27Co73 NWs/C, respectively, after 5000 s in MOR, much larger than that of commercial Pt/C (10% activity retention). There was about 26.1% and 24.8% activity retention of Pt27Co73 NWs/C and Pt53Co47 NWs/C, respectively, after 5000 s in EOR, much larger than that of commercial Pt/C (9% activity retention). The MOR current densities of Pt53Co47/C catalyst and Pt27Co73/C catalyst were 110.65 mA mg−1 and 59.92 mA mg−1 after 5000 s, which were 5.84 and 3.16 times higher than that of commercial Pt/C (18.95 mA mg−1), respectively (Figure 5a). The EOR current density of catalyst Pt27Co73/C (118.88 mA mg−1) and Pt53Co47/C (86.48 mA mg−1) catalyst were 5.47 and 3.98 times that of commercial Pt/C (21.73 mA mg−1) after 5000 s, respectively (Figure 5b). Moreover, compared with recently reported electrocatalysts [42,43,44,45,46,47], the Pt53Co47 NWs/C catalyst and Pt27Co73 NWs/C catalyst also exhibited excellent stability under the same conditions (Table 3 and Table 4). CA tests of the Pt53Co47/C for MOR were extended to 7500 s at 0.65 V vs. RHE. The current densities remained 91.4 mA mg−1 for MOR after 7500 s (Figure 5c). On the other hand, the electronic transfer rate was notably improved, due to the synergistic electronic interaction between Pt and Co atoms of PtnCo100−n/C catalyst. As a consequence, these advantages enabled the catalyst to achieve superior catalytic performance and durability.
Table
Table 3. Stability comparison of Pt53Co47 NWs/C and Pt-based electrocatalysts for MOR.
Table 3. Stability comparison of Pt53Co47 NWs/C and Pt-based electrocatalysts for MOR.
CatalystElectrolyteCA Stability (Activity Retention)PotentialReference
G@(PEI/Au) 3.5 @Pt0.5 M H2SO4 +
1 M methanol		~5.4% after 2000 s0.60 V (vs. SCE)[42]
Pt95Co5 NWs~7.0% after 3600 s0.60 V (vs. SCE)[43]
PdRuPt NWs0.1 M HClO4 +
0.5 M methanol		~16.2% after 5000 s0.60 V (vs. SCE)[44]
Pt53Co47 NWs/C~22.3% after 5000 s0.65 V (vs. SCE)This work
The excellent MOR and EOR activity and stability of PtnCo100−n NWs were mainly determined by the synergistic effect of Pt and Co bimetallic and the defect-rich nanowire structure. The ultrafine and ultrathin nanowire structure fully exposed the active sites. Ultrathin NWs with Boerdijk–Coxeter structure have different crystal plane orientations of the (111)-dominant facets that can control the electronic structure and generate lattice strain, which is beneficial to improve the performance of MOR and EOR.

4. Conclusions

In conclusion, we demonstrated a simple one-step hydrothermal method for the synthesis of ultrathin PtnCo100−n NWs with adjustable compositions. With lattice strain and dominating (111) facets, ultrathin PtnCo100−n NWs demonstrated significant MOR and EOR activity and stability while also enhancing alcohol oxidation catalysis. PtnCo100−n NWs with controlled compositions have a low starting potential and enhanced MOR and EOR activity because of the robust electronic interaction between metals. The Pt53Co47/C exhibited the highest MA of 2.15 A mg Pt−1, which was 1.38-fold and 4.78-fold higher than that of Pt27Co73/C and commercial Pt/C for MOR. The Pt27Co73/C exhibited the highest SA of 3.31 mA/cm2, which was 1.655-fold and 4.60-fold higher than that of Pt53Co47/C and commercial Pt/C for MOR. The Pt27Co73/C exhibited the largest MA value (2.11 A mg−1) and largest SA (1.44 mA/cm2) of EOR, which were about 3.91-fold and 1.67-fold that of Pt/C, respectively. The current densities of Pt27Co73/C and Pt53Co47 NWs/C were much higher than that of commercial Pt/C after 5000 s tests. This study provides an ideal strategy for adjusting the composition of Pt-based alloys. We believe that this study will offer good insights for the preparation of fuel cell electrocatalysts with excellent performance and remarkable durability and will promote the future development of fuel cell electrocatalysts for energy conversions.

Author Contributions

Formal analysis, X.Y.; Data curation, X.B. and Y.L.; Writing—original draft, W.W.; Writing—review & editing, F.C.; Supervision, L.Y. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Science Foundation of China (Grant No. 21908045), the 111 Project (Grant No. D17007) and Henan Center for Outstanding Overseas Scientists (Grant No. GZS2022017).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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Materials 16 00840 g001 550
Figure 1. TEM images of Pt27Co73 (a), Pt53Co47 (b), Pt70Co30 (c). HR-TEM images of Pt27Co73 (d), Pt53Co47 (e) and Pt70Co30 (f) with lattice fringes.
Figure 1. TEM images of Pt27Co73 (a), Pt53Co47 (b), Pt70Co30 (c). HR-TEM images of Pt27Co73 (d), Pt53Co47 (e) and Pt70Co30 (f) with lattice fringes.
Materials 16 00840 g001
Materials 16 00840 g002 550
Figure 2. (a) XRD patterns of NWs. (b) Lattice parameters for NWs on the relative composition of Pt%. XPS spectra and deconvoluted peaks in the regions of (c) Pt 4f and (d) Co 2p. The international standard (C 1s) was used to calibrate the peak position.
Figure 2. (a) XRD patterns of NWs. (b) Lattice parameters for NWs on the relative composition of Pt%. XPS spectra and deconvoluted peaks in the regions of (c) Pt 4f and (d) Co 2p. The international standard (C 1s) was used to calibrate the peak position.
Materials 16 00840 g002
Materials 16 00840 g003 550
Figure 3. (a,c) CV curves of Pt27Co73/C, Pt53Co47/C, Pt70Co30/C, Pt/C and commercial Pt/C in 0.1 M HClO4 + 0.5 M CH3OH/C2H5OH solution purged with N2-saturated solution; (b,d) mass activity and specific activity data of methanol oxidation and ethanol oxidation.
Figure 3. (a,c) CV curves of Pt27Co73/C, Pt53Co47/C, Pt70Co30/C, Pt/C and commercial Pt/C in 0.1 M HClO4 + 0.5 M CH3OH/C2H5OH solution purged with N2-saturated solution; (b,d) mass activity and specific activity data of methanol oxidation and ethanol oxidation.
Materials 16 00840 g003
Materials 16 00840 g004 550
Figure 4. CV curves (a) with the corresponding ECSA (b) of Pt27Co73/C, Pt53Co47/C, Pt70Co30/C and commercial Pt/C in 0.1 M HClO4 solution.
Figure 4. CV curves (a) with the corresponding ECSA (b) of Pt27Co73/C, Pt53Co47/C, Pt70Co30/C and commercial Pt/C in 0.1 M HClO4 solution.
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Materials 16 00840 g005 550
Figure 5. Electrocatalytic durability of the Pt27Co73/C, Pt53Co47/C and commercial Pt/C. Current-time curves of these catalysts recorded at 0.65 V. (a,c) chronoamperometric tests for MOR in 0.1 M HClO4 + 0.5 M methanol. (b) chronoamperometric tests for EOR in 0.1 M HClO4 + 0.5 M ethanol.
Figure 5. Electrocatalytic durability of the Pt27Co73/C, Pt53Co47/C and commercial Pt/C. Current-time curves of these catalysts recorded at 0.65 V. (a,c) chronoamperometric tests for MOR in 0.1 M HClO4 + 0.5 M methanol. (b) chronoamperometric tests for EOR in 0.1 M HClO4 + 0.5 M ethanol.
Materials 16 00840 g005
Table
Table 1. Comparison of MOR activities of various catalysts.
Table 1. Comparison of MOR activities of various catalysts.
CatalystElectrolyteMA
(A/mgPt)		SA
(mA/cm2)		Reference
Pt69Ni16Rh15NWs/C0.1 M HClO4 + 0.5 M methanol1.722.49[32]
UV-Pt@TONR/GN0.5 M H2SO4 + 1 M CH3OH1.943.16[33]
Pd9Ru@Pt/FGN0.881-[34]
1D PtFe alloy0.1 M HClO4 + 0.5 M Methanol1.65-[35]
Pt27Co73/C0.1 M HClO4 + 0.5 M ethanol1.563.31This work
Pt53Co47/C2.152.00This work
Table
Table 2. Comparison of EOR activities of various catalysts.
Table 2. Comparison of EOR activities of various catalysts.
CatalystElectrolyteMA
(A/mgPt)		SA
(mA/cm2)		Reference
PtSn/XC-720.5 M H2SO4 + 1 M ethanol0.76NA[36]
Pt-Mo-Ni NWs0.5 M H2SO4 + 2 M ethanol0.872.57[37]
PtRhNi/C 0.34NA[38]
PtCu2.1 NWs1.022.16[39]
Pt27Co73/C0.1 M HClO4 + 0.5 M ethanol2.111.44This work
Pt53Co47/C0.820.77This work
Table
Table 4. Stability comparison of Pt27Co73 NWs/C and Pt-based electrocatalysts for EOR.
Table 4. Stability comparison of Pt27Co73 NWs/C and Pt-based electrocatalysts for EOR.
CatalystElectrolyteCA Stability (Activity Retention)PotentialReference
Pt HCCLV0.5 M H2SO4 +
1 M ethanol		~27.0% after 2000 s0.60 V (vs. Ag/AgCl)[45]
Pt3Sn/GO~21.7% after 3000 speak potential[46]
Octahedral
Pt2.3Ni/C		0.1 M HClO4 +
0.5 M methanol		~14.7% after 1800 s~0.63 V (vs. RHE)[47]
Pt27Co73 NWs/C~25.7% after 5000 s0.65 V (vs. SCE)This work
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Wang, W.; Bai, X.; Yuan, X.; Liu, Y.; Yang, L.; Chang, F. Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis. Materials 2023, 16, 840. https://doi.org/10.3390/ma16020840

AMA Style

Wang W, Bai X, Yuan X, Liu Y, Yang L, Chang F. Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis. Materials. 2023; 16(2):840. https://doi.org/10.3390/ma16020840

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Wang, Wenwen, Xinyi Bai, Xiaochu Yuan, Yumin Liu, Lin Yang, and Fangfang Chang. 2023. "Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis" Materials 16, no. 2: 840. https://doi.org/10.3390/ma16020840

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