Self-supported film catalyst integrated with multifunctional carbon nanotubes and Ni-Ni(OH)₂ heterostructure for promoted hydrogen evolution

In order to reduce energy consumption in water electrolysis, it is of great importance to design active and stable electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution, especially based on earth-abundant metal. Here we integrate carbon nanotubes (CNTs) and Ni-Ni(OH)₂ heterostructure multifunctional components to design a self-supported 3D CNTs-Ni-Ni(OH)₂ catalyst for HER by composite deposition and subsequent in-situ oxidation. In alkaline solution, this designed CNTs-Ni-Ni(OH)₂ catalyst exhibits 0 mV onset overpotential, and overpotentials of 65 mV and 109 mV at 10 and 50 mA/cm² respectively. Electrochemical measurements, characterizations, and simulation results attribute the outstanding performance to the incorporation of CNTs and heterostructure. CNTs induce the formation 3D catalytic surface, enhance electrochemical active surface area, and more importantly weaken the adsorption of H. Moreover, the formation of heterostructure, especially reversible Ni(OH)₂, supplies active sites and adjusts the adsorption strength of H atom to an optimal value. CNTs and heterostructure synergistically facilitate water adsorption, promote water dissociation, and accelerate H₂ desorption. Significantly, integration of multifunctional components supplies a distinct strategy for development of cost-effective electrocatalyst with outstanding performance.