Porous heterojunction CoSe2–MoSe2 nanosheet arrays for electrocatalytic oxygen evolution

Oxygen evolution reaction (OER) is an important half-reaction of many actual processes, which has the slow kinetics of four-electron process. Interface engineering as an effective method can accelerate the slow kinetics of oxygen evolution reaction. In this paper, CoSe 2 –MoSe 2 porous nanosheet arrays with heterostructures were synthesized on carbon cloth by ion exchange and vapor phase selenization using Co-MOF as template. Due to the porous two-dimensional structure, the electron diffusion path is shortened and the self-supporting electrode has excellent conductivity. When catalyzing OER in 1 M KOH solution, the CoSe 2 –MoSe 2 delivers an overpotential of 278 mV at 10 mA cmm 2 , and Tafel slope of 61.2 mV dec −1 , making catalytic activity a better result than commercial RuO 2 . In addition, the decay of the catalytic activity is negligible after 24 h of continuous electrolysis. This work provides a method for the design of porous bimetallic selenide self-supporting oxygen evolution electrocatalysts.