Ni-doped ZnCo2O4 atomic layers to boost the selectivity in solar-driven reduction of CO2

Regulating the selectivity of CO 2 photoreduction is particularly challenging. Herein, we propose ideal models of atomic layers with/without element doping to investigate the effect of doping engineering to tune the selectivity of CO 2 photoreduction. Prototypical ZnCo 2 O 4 atomic layers with/without Ni-doping were first synthesized. Density functional theory calculations reveal that introducing Ni atoms creates several new energy levels and increases the density-of-states at the conduction band minimum. Synchrotron radiation photoemission spectroscopy demonstrates that the band structures are suitable for CO 2 photoreduction, while the surface photovoltage spectra demonstrate that Ni doping increases the carrier separation efficiency. In situ diffuse reflectance Fourier transform infrared spectra disclose that the CO 2 ·− radical is the main intermediate, while temperature-programed desorption curves reveal that the ZnCo 2 O 4 atomic layers with/without Ni doping favor the respective CO and CH 4 desorption. The Ni-doped ZnCo 2 O 4 atomic layers exhibit a 3.5-time higher CO selectivity than the ZnCo 2 O 4 atomic layers. This work establishes a clear correlation between elemental doping and selectivity regulation for CO 2 photoreduction, opening new possibilities for tailoring solar-driven photocatalytic behaviors.