Facile Synthesis of Ni3+/Co3+ Ion-Doped Zn2SnO4 Microspheres toward Efficient Photocatalytic CO2 Reduction

The photocatalytic reduction of CO2 into hydrocarbons is a promising solution for the energy crisis and greenhouse gas emissions. Thus, the fabrication and development of a new type of photocatalyst is of great importance for the practical application of CO2 reduction. Herein, we report a facile synthesis of Zn2SnO4 (ZTO) microspheres doped with Co3+ ions or Ni3+ ions. The doped Co3+/Ni3+ ions substitute the lattice Zn/Sn ions. DFT calculations and experimental results reveal that the doped Co3+/Ni3+ ions would induce new doping energy levels in the band gap, extend the light response from the UV to the visible region, and separate the charge carriers. As a result, compared with pure ZTO, the photocatalytic activity of a CO2 reduction into CH4 is significantly improved for Co-doped ZTO (Co-ZTO) and Ni-doped ZTO (Ni-ZTO).