Surface gradient diffusion S doping of CuCo2O4 microflowers by an in situ topotactic engineering strategy for CO2 photoreduction

Photocatalysis is an effective means to convert CO2 and solar energy into high value-added chemicals. Herein, the surface gradient S doped CuCo2O4 microflowers were fabricated by an in situ topotactic engineering strategy. This photocatalyst presented CO2 photoreduction with a satisfying activity (5 h, 181 μmol) and stability (94.5% retention). Additionally, the theoretical calculations indicated the fomated M-S bond could be favorbale to facilitate the initial CO2⁎ binding and promote the formation of COOH⁎ intermediates. This work provides a novel strategy for the fabrication of effective photocatalysts and highlights an in-depth understanding of micro-level regulation towards photocatalytic overall performance. [Display omitted] •Gradient S doping 3D CuCo2O4 microflowers were obtained by in situ topotactic transformation.•Photogenerated carriers were effectively separated by an oriented built-in field.•S doping both encouraged the initial binding CO2⁎ and reduced the activation energy barriers.•Grad-S-CuCo2O4 behaved promoted CO2 photoreduction with well stability and selectivity.