Lattice strain engineering in ZnGa2O4 for selective CO2 photoreduction enhancement

Photocatalytic CO2 reduction requests efficient separation and migration of photogenerated carriers. However, the recombination of photogenerated electrons and holes still limits the improvement of photocatalytic performances. In this work, an enhanced built-in polarization electric field induced by introducing lattice strain was used to promote the separation of photogenerated electrons and holes, thus achieving an improved selective CO2 photoreduction performances. The lattice strain could be easily adjusted by controlling the calcination temperature when preparing ZnGa2O4 catalyst. Compared with ZnGa2O4 prepared through calcination at high temperature, ZnGa2O4 prepared through calcination at low temperature possessed larger lattice strain and stronger built-in polarization electric field, leading to an enhanced photoreduction from CO2 to CO with nearly 100 % product selectivity. This study highlights the important role of lattice strain and polarization electric field on carrier separation and migration and provides efficient strategy for designing photocatalysts with high performances.