Chemical Strain Engineering of Copper Atoms on Continuous Three-Dimensional-Nanopatterned Nickel Nitride to Accelerate Alkaline Hydrogen Evolution

Abstract

Maximizing electrocatalytic activity by incorporating heteroatoms into the microstructures of non-noble metal catalysts is vital for their application in industrial water-alkali electrolyzers, yet modulation of the catalytic properties by the synergistic effects of three-dimensional (3D) nanopatterning and the incorporation of heteroatoms remains challenging. Here, we fabricated a tunable Cu atom-incorporated continuous 3D-nanopatterned nickel nitride (Ni3N) and investigated its electrocatalytic activity for the alkaline hydrogen evolution reaction. By altering Cu atom incorporation and the synergistic effect between lattice strain and 3D nanopatterning, efficient electrocatalytic activity was achieved. The resulting catalyst delivered an overpotential of 48 mV at a current density of 10 mA/cm2 and a Tafel slope of 51 mV/dec, which is similar to those of the benchmark electrocatalyst Pt/C (overpotential = 27 mV and Tafel slope = 29 mV/dec). The excellent electrocatalytic activity of copper atom-incorporated 3D-nanopatterned nickel nitride (CuNi2N-3DNi) was attributed to manipulation of the electronic structure by inducing lattice strain, which reduces the energy barrier for the adsorption of H2O, prompting balanced adsorption-desorption of the intermediate hydrogen H* by lowering the Gibbs free energy (ΔGH* = −0.06 eV). This work provides an effective strategy to improve the electrocatalytic activity of synthesized 3D microstructure catalysts incorporating a large area by precise strain engineering and nanopatterning. © 2023 American Chemical Society.