Regulation of d-band centers in layered double hydroxide nanocages through Zn doping for improved photocatalytic CO₂ reduction

Efficient photocatalytic CO₂ reduction to valuable fuels is an ideal strategy for addressing the energy and environmental crisis. Herein, we developed the Zn-incorporated hollow nanocages, assembled by NiCo-layered double hydroxide ultrathin nanosheets (NiCoZn_x-LDH), as highly efficient photocatalysts. Spectroscopic characterization and theoretical calculations demonstrate that Zn doping leads to an upshift of the d-band center of Ni-Co dual sites, increasing unoccupied antibonding orbitals and enhancing the binding strength of adsorbates. Therefore, NiCoZn_0.10-LDH with the upgrade of d-band shows a lower ·CO₂^– formation energy, resulting in a more effective stabilization of the rate-limiting ·CO₂^– intermediate. This boosts the overall CO₂ photoreduction performance over NiCoZn_0.10-LDH, resulting in a high CO yield of 158.1 μmol·g^–1·h^–1 with 92.1% selectivity. Our findings enrich the fundamental understanding of the CO₂ activation mechanism and provide additional insights into the d-band center theory to enhance the photocatalytic activity for overall CO₂ reduction.