Electrocatalytic hydrogen evolution reaction on graphene supported transition metal-organic frameworks

Abstract

A highly efficient, cost-effective, and durable electrocatalysts based on CoNi metal–organic framework (MOF) nanosheets on highly porous conductive graphene (PCG) is introduced for the hydrogen evolution reaction (HER). The electrocatalyst was fabricated by template-assisted chemical vapor deposition of graphene followed by solvothermal growth of CoNi-MOF nanosheets. Highly porous 3D structure of PCG with open channels of 200–500 nm sizes provided high active surface area and facilitates gas evolution. In a highly alkaline solution, the electrocatalyst exhibits superior figures of merits, e.g. overpotential of 265 mV at −10 mA cm−2 and Tafel slope of 44.5 mV dec-1, to existing hydrogen electrocatalysts. The resulting electrocatalyst exhibits the synergetic effect of CoNi-MOF and electroactive catalytic surface area of PCG on promoting the outstanding electrocatalytic performance. Electrochemical impedance spectroscopy evidenced high diffusion rate and fast charge transfer capability of CoNi-MOF-PCG electrode. This study opens up new possibility for design and fabrication of highly efficient bimetallic electrocatalysts for water splitting applications.