Controlled synthesis and fine-tuned interface of NiS nanoparticles/Bi2WO6 nanosheets heterogeneous as electrocatalyst for oxygen evolution reaction

Heterojunction engineering is one of the commonly used methods for developing electrocatalyst to enhance catalytic activity and stability due to the unique interfacial coupling synergistic. Herein, a strong-coupling 0D/2D NiS/Bi2WO6 heterogeneous electrocatalyst was successfully synthesized through a facile hydrothermal and calcination route. Electrochemistry results revealed that the NiS/Bi2WO6-4 catalyst not only exhibited competitive OER catalytic activity with smaller overpotential (527 mV) and lower Tafel slope (238 mV dec(-1)) but also delivered long-term stability (at 1.73 V vs. RHE for 13 h). Such excellent properties are mainly due to (1) the substantial active sites are provided by NiS nanoparticles evenly anchored on Bi2WO6 nanosheets, (2) the O-Ni-S bond structure acts as the bridge in heterointerface, which improves the charge and mass transfer rate as well as stabilizes the heterostructure, (3) Most importantly, the bonding of Ni and O changes the valence-bond environment around the nickel species, which is more conducive to balance between the adsorption of OH- and the desorption of O-2 in the oxygen evolution reaction. This non-precious NiS/Bi2WO6 heterojunction catalyst is designed with the 0D/2D heterointerface engineering, which may open a new train of thought to design new promising and highly efficient OER electrocatalysts.