Construction of the Sn-doped defect pyrochlore oxide KNbMoO6·H2O/g-C3N4 composite and its photocatalytic reduction of CO2

Abstract

In order to cope with the gradually increasing greenhouse effect and energy issues, it is remarkably desired to generate new semiconductors for photocatalysis for the conversion of CO₂ into valuable fuels. Defect pyrochlore oxides are considered potential photocatalysts. Herein, the defective pyrochlore oxide KNbMoO₆·H₂O (KNMO) was synthesized via a hydrothermal/solvothermal route for the first time, and then a g-C₃N₄ coupled Sn-doped KNbMoO₆·H₂O (SKNMO) (SKNMO/g-C₃N₄) composite was successfully prepared. In comparison with the original KNMO, SKNMO/g-C₃N₄ presents a higher photocatalytic performance, and the photocatalytic conversion efficiency of CO₂ to CO has quadrupled. On the basis of UV-vis and photoluminescence results, we deduced that the improvement of photocatalytic activity is mainly due to the extended visible light response and intensive charge separation. This work implies that modified defect pyrochlore oxides have the potential to become a new type of photocatalyst, which can be applied in the fields of environmental remediation and energy regeneration.