Morphology control of Ni(OH)2-TiO2 nanosheet array and its excellent electrochemical hydrogen evolution performance

Abstract

Aiming at the kinetic bottleneck of hydrogen evolution reaction in hydrogen production by electrolysis of water, Ni(OH)₂-TiO₂ composites were successfully prepared on nickel foam (NF) substrate by two-step hydrothermal method. By adjusting the concentration of nickel source and reaction conditions, the composite catalysts with excellent morphology and structure were constructed. The Ni(OH)₂-TiO₂ catalyst prepared under the optimized conditions has an overpotential of only 63 mV at the current density of 10 mA·cm⁻², showing lower Tafel slope, higher double layer capacitance and excellent reaction kinetics. The results of density functional theory (DFT) revealed the phenomenon of charge transfer inside the composite and the influence of interface effect on the electron structure, and further confirmed that the electrons transfer from Ni(OH)₂ to TiO₂ optimized the charge distribution inside the composite, promoted the charge transfer at the interface, and reduced the activation energy of catalytic reaction.