One-step synthesis of dendritic nanostructured single crystal NiSe electrocatalyst for hydrogen evolution reaction

A novel dendritic nanostructure NiSe has been synthesized for electrocatalytic hydrogen evolution reaction (HER) through a hydrothermal method. The micromorphology and microstructure characterizations show that the branches of the dendritic NiSe are epitaxially grown on the trunk, and individual nickel selenide dendrites have three-dimensional structures with four branches in short axes. The nanostructures of each branch are paralleled to each other in the same plane, and are perpendicular to the trunk with the same crystal orientation. The dendritic NiSe catalyst demonstrates highly efficient HER activity with a low overpotential of 191 mV and a small Tafel slope of 47 mV dec⁻¹ in acidic solutions. The remarkable enhancement of the dendritic NiSe in the HER performance can be attributed to its dense dendritic nano-structure, and high specific surface area, which provide effective diffusion channels and much more catalytic sites towards the HER. This achievement provides a new method for producing cheap and efficient dendritic nanostructures catalysts for water splitting.