Promoted charge separation from nickel intervening in [Bi2O2]2+ layers of Bi2O2S crystals for enhanced photocatalytic CO2 conversion

Improving the separation efficiency of charge carriers and abilities for CO2 adsorption and activation of photocatalysts is still a challenge. Herein, we successfully introduced Ni2+ into [Bi2O2]2+ layers in Bi2O2S crystals via a facile hydrothermal reaction, which markedly enhanced their photocatalytic CO2 reduction performance. With full-spectrum light irradiation, the photocatalytic CO2 reduction activity of the optimized sample NBOS-0.24 is ca. 13 times and 8 times higher than that of pristine Bi2O2S under air and 99 % CO2 atmosphere, respectively. Both experimental results and theoretical calculations verify that implanting of Ni2+ into [Bi2O2]2+ layers generates new band gap states and increases the concentration of oxygen vacancies in Bi2O2S photocatalyst, which boosts the photogenerated charge separation efficiency and greatly improves the CO2 adsorption and activation capacities over the photocatalyst. This work shows a promising [Bi2O2]2+-containing photocatalyst and reveals the mechanism of introducing metal ions to boost its photocatalytic CO2 reduction performance.