Acid-Stable CoWO4/WO3-Microrod Coated by a Thin Carbon-Layer as Efficient Pt Co-Catalysts for Methanol Oxidation and Oxygen Reduction

• Published in: Jiégòu huàxué Vol. 41; no. 7; pp. 2207059 - 2207067
• Main Authors: Li, Jiahuan, Xie, Jiahao, Wang, Xinyu, Dai, Ying, Xu, Xiaoqin, Liu, Jin, Cai, Zhuang, Meng, Xin, Zou, Jinlong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022; Key Laboratory of Functional Inorganic Material Chemistry,Ministry of Education of the People's Republic of China,School of Chemistry and Materials Science,Heilongjiang University,Harbin 150080,China%School of Civil Engineering,Heilongjiang Institute of Technology,Harbin 150050,China
• Subjects: acid resistance; methanol-tolerance; oxygen vacancies; strong metal-support interaction; thin carbon-layer; thin carbon-layer; acid resistance; methanol-tolerance; strong metal-support interaction; oxygen vacancies
• ISSN: 0254-5861
• DOI: 10.14102/j.cnki.0254-5861.2022-0104

Insufficient activity and instability (poisoning) of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions (MOR/ORR) impede the development of direct methanol fuel cells. Here, CoWO4 nanoparticles-loaded WO3 microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR. WO3 grows along the (110) crystal plane to form microrod (diameter of ~0.6 um), which is coated by a carbon-layer (~5 nm). Pt-CoWO4/WO3@NCL-mr (850 °C) shows a higher mass activity (2208 mA mg−1pt) than the commercial Pt/C (659.4 mA mg−1pt). CoWO4/WO3 heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites (promising stability). Pt-CoWO4/WO3@NCL-mr (850 °C) has higher half-wave (0.46 V) and onset (0.54 V) potentials than Pt/C (0.41 and 0.50 V) for ORR. The microrod structure of CoWO4/WO3@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO4 (Co2+) for ORR in acid media. This study provides insights not only into the synthesis of acid-resistant WO3@NCL microrod as active Pt co-catalyst, but also into the effective utilization of surface oxygen vacancies and Co2+ for MOR/ORR. The micro-rod-shaped CoWO4/WO3@NCL promotes the dispersibility of Pt particles, and the hydrogen overflow effect between Pt and WO3 facilitates the formation of HxWO3. Synergy between Pt and Co2+ (CoWO4) obtains a durable activity for ORR. CoWO4/WO3@NCL-mr support makes Pt have a good corrosion resistance in acid media.