Hierarchical nanoassembly of Ni/MoS2@Ni12P5/ZnP2 achieved by a plasma assisted phosphorization with highly improved electrocatalytic activity for overall water splitting

Herein, Zn single atom supported MoS2 nanosheets growing on nickel foam (NF) is formed by in-situ growth of MoS2 nanosheets and ZIF-8 and high temperature carbonization. And then plasma-assisted-phosphorization is employed to obtain homogeneous nickel phosphide (Ni12P5) and zinc phosphide (ZnP2) heterojunction nano particles (NPs) distributed over the surface of MoS2 nanosheets (P-Ni/MoS2@Ni12P5/ZnP2). The MoS2 nano sheets growing on 3D NF framework benefits the increase of the electrochemically active specific surface, and the uniform distribution of heterojunction Ni12P5/ZnP(2 )NPs exposes more catalytic active sites. Moreover, the heterojunction Ni12P5/ZnP2 NPs obtained by plasma-assisted-phosphorization has smaller size and stronger electronic coupling than that synthesized by the conventional thermal phosphorization (C-Ni/MoS2@Ni12P5/ZnP2 ). Therefore, the as-synthesized P-Ni/MoS2@Ni12P5/ZnP2 shows an excellent bifunctionality catalytic activity for both HER and OER in alkaline solutions, which is highlighted by the overpotential at 82 mV for delivering current density of 10 mA cm(-2 )for HER and 360 mV for delivering 100 mA cm(-2 )for OER. P-Ni/MoS2@Ni12P5/ZnP(2 )exhibits higher electrocatalytic performance and better stability than most previously reported bifunctional catalysts. Furthermore, the catalytic current density of P-Ni/MoS2@Ni12P5/ZnP2 as a bifunctional catalyst assembled single two-electrode-electrolyzer rapidly exceeded 50 mA cm(-2 )at a low cell voltage of 1.62 V, surpassing the commercial RuO2-Pt/C coupled electrolyzer.