Enhancing the Electrocatalytic Activity of Pt/rGO With NixWyC Promoter for Methanol Oxidation.

Metal carbides have similar electronic structure to noble metals near Fermi level. It makes them attractive as electrocatalyst materials. Introducing second metal on metal carbide can further enhance the electrocatalytic behavior. Herein, we report the synthesis of NixWyC supported Pt/rGO electrocatalysts and systematically investigated the role of Ni/W composition on methanol oxidation reaction (MOR) activity and catalyst stability. Experimental and theoretical studies reveal that the amount of Ni content in NixWyC has prodigious effect on both methanol electrooxidation activity and catalyst stability. The first principles calculations imply that Ni modified WC anchored Pt/rGO catalysts can have higher conductivity and low energy barrier for MOR due to increased electron density at Fermi level. The experimental results show NixWyC with Ni/W molar ratios of 1:1 exhibited BET surface area (754 m2 g‒1) and electrochemical active surface area (42 m2 g‒1) among others. Further, the Pt/Ni1W1C-rGO catalyst exhibited good methanol electrooxidation performance with high mass activity of 628.5 mA mgPt-1 and lower onset potential of 0.60 V/RHE. The enhanced activity is attributed to the synergistic interaction among Pt, Ni, WC, and rGO, which weakens CO adsorption while promoting OH adsorption, thereby facilitating efficient CO oxidation and rapid regeneration of active sites.