Boosting electrocatalytic activity of NiSe2 nanosheets by anion-cation dual-doping for highly efficient hydrogen evolution reaction

Abstract

Rational design of low-cost and highly-efficient electrocatalysts is vital for water electrolysis. To date, many works have proved that the electrocatalytic hydrogen evolution reaction (HER) activity of the transition metal chalcogenides (TMCs) can be enhanced by anion or cation doping. However, the effect of anion-cation dual-doping on improving the HER activity of TMCs catalysts is still questionable. Herein, we designed and synthesized a porous (Mo, N)-NiSe2/Nickel foam (NF) nanosheets array by simultaneous doping Mo and N into pyrite-type NiSe2. For (Mo, N)-NiSe2/NF, the incorporation of Mo could significantly increase the specific surface area and active sites of NiSe2 catalyst, whereas N doping was primarily responsible for accelerating the intrinsic reaction kinetics as well as introducing new reactive sites of catalyst. As a result, the porous (Mo, N)-NiSe2/NF nanosheets array exhibited a low overpotential of 82 mV at 10 mA.cm−2, a small Tafel slope of 84.5 mV.dec−1, and a high Cdl of 90.5 mF.cm−2 for HER. Furthermore, the results of “post-HER” XRD, HR-TEM, SEM and XPS demonstrated that the structure, composition and morphology of (Mo, N)-NiSe2/NF remained unchanged after 35 h constant current test. This work highlighted the importance of anion-cation dual-doping in boosting electrocatalytic HER activity of TMCs catalysts.