In situ growth of NiWO4/WO2 nanocrystals on CC for the enhanced electrocatalytic oxidation of methanol

Abstract

Methanol oxidation reaction (MOR) plays a decisive role in the energy conversion efficiency of direct methanol fuel cells (DMFC), so it is very important to develop efficient and cheap electrocatalysts to improve the kinetic limitation of MOR. The self-supported bimetallic composites (NiWO4/WO2-700 @CC) of NiWO4/WO2 nanoparticles grown in situ on carbon cloth (CC) were prepared by hydrothermal and pyrolysis methods. The electrochemical results show that the MOR on the NiWO4/WO2-700 @CC can obtain a current density (j) of 10 mA cm−2 with a driving voltage of only 1.31 V. At 1.6 V, the j of 283.6 mA cm−2 exceeds that of nickel-based bimetallic catalysts reported in the literature. The excellent MOR performance of NiWO4/WO2-700 @CC sample is mainly attributed to its mesoporous and self-supporting structure characteristics, as well as the strong electron interaction between Ni and W. Density functional theory (DFT) calculations indicated that NiWO4/WO2-700 @CC has a higher adsorption capacity for CH3OH, and reduces the energy barrier of the CO* →COOH* step.