Nitrogen and phosphorus Co-doped non stoichiometric cobalt selenides (Co0.85Se) ultrathin nanosheets as highly efficient electrocatalysts for the hydrogen evolution reaction

Two-dimensional (2D) non-stoichiometric cobalt selenide (Co0.85Se) has the specific electrochemical performances of exposing more active sites and the high conductivity, which makes it a unique advantage as promising candidates for hydrogen evolution reaction (HER). Hence, we used the one-step hydrothermal method to synthesize nitrogen-phosphorus co-doped Co0.85Se (N,P-Co0.85Se) ultrathin nanosheets for catalyzing HER. Due to the co-doping of N and P, more active sites were generated, thus making N,P-Co0.85Se ultrathin nanosheets have excellent HER performance. The LSV test results in 1 M KOH showed that the overpotential of N,P-Co0.85Se ultrathin nanosheets was 210 mV under the current density of 10 mA cm-2, 130 mV lower than that of the undoped Co0.85Se nanosheets (340 mV). The N,P-Co0.85Se ultrathin nanosheets also had excellent stability that the overpotential merely increased by 12 mV after 1000 cycles, much lower than that of the un-doped Co0.85Se nanosheets (48 mV). This one-step hydrothermal method can provide an efficient and facile idea for fabrication of various co-doped metal selenide nanocatalysts with high electrocatalytic performance.

Automated summary

Nitrogen-phosphorus co-doped ultrathin nanosheets of Co0.85Se were synthesized using a one-step hydrothermal method. These nanosheets exhibit more active sites and high conductivity, resulting in excellent performance and stability for the hydrogen evolution reaction.