Electrochemical fabrication of ultra-low loading Pt decorated porous nickel frameworks as efficient catalysts for methanol electrooxidation in alkaline medium

Abstract

Developing highly active and durable methanol electrooxidation reaction electrocatalysts for direct methanol fuel cells is crucial to achieve their practical application in future energy storage and conversion. Herein, we demonstrate that a nickel supported Pt-decorated electrode with an ultralow mass loading (1.50 μg cm−2) featuring Ni-Pt hybrid nanoparticles growing on self-reconstructed porous nickel frameworks (Pt/p-Ni) is synthesized via a facile electrochemical activation process. The self-supported Pt/p-Ni exhibits 3.65-fold higher activity for catalyzing the methanol electrooxidation reaction than that of commercial Pt/C with the same Pt loading under alkaline media. The activation approach results in surface rearrangement of Ni substrate to form nanoporous skeletons and highly dispersed Ni-Pt hybrid nanoparticles with a mean size of 4.34 nm grown on the nano-ligaments of the Ni porous skeletons. The porous skeletons decorated with nano-dispersion of Pt significantly increase the surface active sites and, therefore, yield a superior catalytic activity. Experiments coupled with density-functional theory calculations suggest the existence of a strong electronic interaction at the superface of the Pt/p-Ni, which leads to efficiently weaken the adsorption of CO on the catalyst surface and alleviate the COads poisoning of the active sites, resulting in remarkably enhanced methanol electrooxidation activity and durability.