Constructing Ohmic contact in cobalt selenide/Ti dyadic electrode: The third aspect to promote the oxygen evolution reaction

Highlights: • We have designed and developed an Ohmic contact-based hybrid electrode for OER by a facile one-step hydrothermal method. • The Ohmic contact was highly effective to strengthen electrochemical kinetics. • The cobalt selenide/Ti mesh hybrid electrode could provide a current density of 29.6 mA cm⁻² at 1.8 V vs. RHE. Oxygen evolution reaction (OER) is a kinetically slow process for overall water splitting, particularly in neutral electrolyte. Great efforts have been devoted to the control in either composition or mesoscale structure of the nanocatalysts for accelerating the OER performance. However, the interface between the nanocatalysts and current collector, the third aspect to be considered for the design of an OER dyadic electrode, has been less touched till now. As a proof-of-concept study here, we described the importance of constructing an Ohmic contact at the interface of the cobalt selenide nanostructures (as the active components) and the Ti mesh (as the current collector) to significantly promote the OER performance in neutral electrolyte. The cobalt selenide/Ti mesh hybrid electrode could provide a current density of 29.6 mA cm⁻² at an OER overpotential of 570 mV and high durability in neutral medium.