Optimizing the electronic structure of CoN_x via coupling with N-doped carbon for efficient electrochemical hydrogen...

Transition metal nitrides (TMNs) have been regarded as an excellent class of electrocatalysts for hydrogen evolution reaction (HER), but there is still huge room for improvement. In this work, cobalt nitride (CoN_x) coupled with N-doped carbon (NC) and supported by nickel foam (NF) is designed as an efficient HER electrocatalyst (NF/CoN_x@NC). The introduction of NC can not only optimize the electronic structure of CoN_x to boost the intrinsic activity, but also enhance the electronic conductivity and stability of the catalyst. As a result, NF/CoN_x@NC exhibits excellent HER performance. On the one hand, it only needs an overpotential of 69 mV to deliver a current density of 20 mA cm^-2 in 1.0 mol/L KOH, far better than that of CoN_x (182 mV). On the other hand, the electronic conductivity and stability of the catalyst can be significantly enhanced after the introduction of NC. This work has done successful material design with the goal of enhancing the intrinsic activity, electronic conductivity, and stability, which has certain reference and guiding significance for the design of novel transition metal-based electrocatalysts.