Acid-Stable CoWO_(4)/WO_(3)-Microrod Coated by a Thin Carbon-Layer as Efficient Pt Co-Catalysts for Methanol Oxidation and Oxygen Reduction

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,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) 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).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)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 Co WO_(4)/WO_(3)@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 CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.