Ni nanoparticles on active (001) facet-exposed rutile TiO₂ nanopyramid arrays for efficient hydrogen evolution

Abstract

Efficient earth-abundant electrocatalysts for hydrogen evolution reaction (HER) is crucial for realizing cost-effective hydrogen production as a renewable energy source. Herein, we report highly enhanced HER activity of Ni nanoparticles (NPs) on TiO₂ nanopyramid arrays (NPAs). The (001) facets exposed on TiO₂ NPAs provide strong adsorption sites for Ni NPs, and the charge redistribution between Ni NPs and TiO₂ tunes the adsorption energy of HER intermediates, optimizing HER activity as manifested by low overpotential of 88 mV at 10 mA cm⁻² and Tafel slope of 78 mV dec⁻¹. The modification of the Ni/TiO₂ NPAs with nitrogen-doped carbon quantum dot layer forms an active interface of Ni-N-C bonds, which enhances the stability and activates the Ni NPs on inactive {110} facets to further lower the overpotential to 65 mV at 10 mA cm⁻². This work provides a new insight into rational design of non-noble metal electrocatalysts for highly promoted hydrogen production.