SnO2 nanodots-embedding and KSCN-assisted re-calcination synergistically boost photocatalytic CO2 reduction of carbon nitride

In this work, a heterojunction of SnO2 nanodots embedded on K-doped carbon nitride (CN) was prepared via wet chemistry and two-step calcination processes for photoreduction of CO2. Experiments and theoretical calculations confirmed that both of SnO2-embedding and KSCN-assisted re-calcination could enhance visible light absorption and facilitate photogenerated charge separation, enabling constructed SnO2/K-CN had good CO2 adsorption and activation performances. The optimized photocatalyst loaded with 1.92 wt% SnO2 displayed high CO2 reductive activity with CO and CH4 yields of 80.4 and 1.4 μmol g−1, respectively after 3 h in the presence of 0.5 mL water. Such CO2 reductive activity was not reduced in four repeated tests within the 45 day period. This work provides a new method to construct CN-based heterojunction for enhancing CO2 reductive capacity and stability.