In-situ phosphating Co@Nitrogen-doping graphene boosts overall water splitting under alkaline condition

It is still challenging to design and synthesize highly efficient and noble-metal-free electrocatalysts for hydrogen/oxygen evolution reaction (HER/OER). Herein, we developed an in-situ phosphating [email protected] graphene to obtain N and P co-doped carbon-coated cobalt phosphide ([email protected],PC) that could be used for overall water splitting. The unique 3D porous structure of [email protected],PC is characterized by a large number of active catalytic sites. High wettability of catalyst in electrolyte solution facilitates the transfer of ions. The synergism between the CoP cores and N, PC shells improves the total hydrolysis performance of the electrocatalyst during the HER and OER. At the current densities of 10 mA/cm2 (1 M of KOH), the HER overpotential recorded for the [email protected],PC is 113 mV, and the OER overpotential is 320 mV. The cell voltage of the [email protected],PC as bifunctional electrode for overall water splitting is 1.67 V (at 10 mA/cm2), which is close to that of the full noble-metal electrode (RuO2 || Pt/C, 1.58 V). The [email protected], PC bifunctional catalyst can be potentially used to replace noble-metal electrodes to realize water splitting.