CHEMICAL SCIENCE

Coupled bifunctional catalysis and strain effects promote Pt to efficiently catalyze methanol oxidation


On June 21, 2022, Researcher Yang Jun of the Institute of Process Engineering, Chinese Academy of Sciences, founded a new energy journal at Tsinghua University, Nano Research Energyhttps://www.sciopen.com/journal/2790-8119posted under the title“Light doping of tungsten into copper-platinum nanoalloys for boosting their electrocatalytic performance in methanol oxidation”Latest research results.

Direct methanol fuel cell (DMFC) is a kind of power generation device that directly converts the chemical energy of methanol oxidation reaction into electrical energy, which is mainly composed of cathode, anode, proton exchange membrane and bipolar plate, etc. Its structure is simple, convenient and flexible, and the working time depends only on the amount of fuel carried and is not limited to the rated capacity of the battery, which has been favored by the industry in recent years. DMFC in the power generation process, without going through the Carnot cycle, has the advantages of high energy conversion efficiency, low emissions and no noise, in addition to the use of room temperature, fuel carrying and replenishment convenience, volume and weight than high energy density advantages, especially suitable for small movable and portable power supply, in the field of defense, energy and communications has a potential broad application prospects. A major obstacle to the commercialization of DMFCs is the slow kinetics of its anodized methanol oxidation reaction, a problem that is particularly acute during cryogenic operation. In addition, carbon monoxide-like species (CO-like species) produced during methanol oxidation are easily and strongly adsorbed on the surface of the Pt-based catalyst, causing catalyst poisoning inactivation.

Fig. 1: (a) Pt XPS valence band spectrum of CuWPt ternary alloy and its control sample, from which the d-band center of Pt can be calculated; (b) The corresponding CO electrochemical peeling curve in the acidic medium can be judged from which the adsorption status of CO at the active site can be judged.

In view of the above problems, yang Jun,200 researchers at the State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, coupled the bifunctional catalytic mechanism and lattice compression strain effect, and reduced the d-band center of the active Pt component by doping a small amount of W in the CuPt alloy system, weakening the chemical adsorption of carbon monoxide species on its surface, and greatly improving its performance in catalyzing methanol oxidation at room temperature. As shown in Figure 1, in the ternary system they prepared, a small amount of W can not only reduce the d-band center of Pt, weaken the adsorption of CO, but also purify the Pt catalytic site through a “hydrogen spillover effect” to further improve its catalytic stability. Studies have shown that when the molar ratio of Cu/W/Pt reaches an optimal combination of 21/4/755, the specific activity and mass activity of CuWPt ternary alloy nanoparticles on methanol oxidation can reach 2.5 mA·cm–2 and 2.11 A·mg–1, respectively, and have excellent stability, and the performance far exceeds their CuPt binary alloy control samples, commercial Pt/C catalysts and Pt-based alloy materials reported in recent years. Based on this, they assembled DMFC but batteries with CuWPt ternary alloys as the anode catalyst, and the cell open circuit voltage and power density reached 0.6 V and 24.3 mW·cm–2 at room temperature, respectively, which also far exceeded the control batteries with commercial Pt/C as the anode catalyst. This study demonstrates the potential of additional additives to enhance the electrocatalytic performance of precious metals, providing a viable option for the synthesis of highly efficient precious metal-based electrocatalysts.

Related paper information:

Liu, D. Y.; Zeng, Q.; Hu, C. Q.; Chen, D.; Liu, H.; Han, Y. S.; Xu, L.; Zhang, Q. B.; Yang, J. Light doping of tungsten into copper-platinum nanoalloys for boosting their electrocatalytic performance in methanol oxidation. Nano Res. Energy 2022, DOI: 10.26599/NRE.2022.9120017. https://doi.org/10.26599/NRE.2022.9120017

As a sister journal of Nano Research, Nano Research Energy (ISSN: 2791-0091; e-ISSN: 2790-8119; Official website: https://www.sciopen.com/journal/2790-8119It was launched in March 2022 and is co-edited by Professor Qu Liangti of Tsinghua University and Professor Chunyi Zhi of the City University of Hong Kong. Nano Research Energy is an international multidisciplinary, all-English open access journal, focusing on the cutting-edge research and application of nanomaterials and nanoscience technology in new energy-related fields, benchmarking against the top international energy journals, and committed to publishing high-level original research and review papers. Before 2023No APC feesTeachers are welcome to submit articles. Please contact: NanoResearchEnergy@tup.tsinghua.edu.cn.

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