Lattice-strained nickel hydroxide nanosheets for the boosted diluted CO2 photoreduction

Abstract

The photoreduction of diluted CO₂ into value-added solar fuel is a discipline at the forefront of energy and environmental research. However, this exploration largely suffers from unsatisfactory activity and selectivity. Herein, lattice-strained nickel hydroxide nanosheets (NSs) were successfully constructed via a vanadium-doped strategy toward the photoreduction of diluted CO₂. X-ray absorption fine structure spectroscopy and Williamson–Hall analysis based on X-ray diffraction revealed the formation of lattice strain on the surface of the Ni(OH)₂ NSs. Consequently, the lattice-strained sample exhibited the highest CO production yield of 20.7 μmol with a CO selectivity of 97% after 3 h in pure CO₂, which were almost 4 and 1.3 times those of its parent Ni(OH)₂ NS. Even in diluted CO₂ (0.1 atm), it exhibited a CO production rate of 5.8 μmol h⁻¹ with a CO selectivity of 91.3%, surpassing most previous works in pure CO₂. Further characterizations revealed that the lattice strain could greatly improve the CO₂ adsorption and activation, and the separation efficiency of the photogenerated carriers, thus leading to an enhancement in the carbon dioxide reduction activity. This work discloses a clear atomic-level correlation between lattice strain and diluted CO₂ photoreduction, which lays a foundation for reinventing their applications in photocatalysis, among other applications.