Highly Efficient Photocatalytic H 2 O 2 Production over a Zn 0.3 Cd 0.7 S/MXene Photocatalyst for Degradation of Emerging Pollutants under Visible-Light Irradiation.

Hydrogen peroxide (H 2 O 2 ) is an ideal green product with a broad range of applications, and visible-light-driven photocatalytic H 2 O 2 production is deemed a sustainable and eco-friendly strategy. Herein, various Zn x Cd 1- x S/MXene photocatalysts with a Schottky junction were prepared for photocatalytic H 2 O 2 production. The obtained Zn 0.3 Cd 0.7 S/MXene (ZCM-0.3) hybrid presented the highest photocatalytic H 2 O 2 production rate in pure neutral water of 1160 μmol h -1 g -1 , which was further improved to 2178.58 μmol h -1 g -1 in the presence of isopropanol as the sacrificial reagent. The experimental results demonstrated that the sufficient visible-light-harvesting ability and appropriate conduction band potential of the Zn 0.3 Cd 0.7 S solid solution, the excellent conductivity and two-electron selectivity of MXene, and the construction of Schottky junctions at the Zn 0.3 Cd 0.7 S/MXene interface resulted in the fast transfer and separation of the photogenerated charge carriers and the targeted reduction of oxygen to H 2 O 2 . The photocatalytic mechanism for H 2 O 2 production was studied and proposed. Moreover, a simple photo-Fenton system consisting of Zn x Cd 1- x S/MXene and ferrous ions (Fe 2+ ) was constructed and applied for the degradation of various emerging pollutants, which also performed effectively and exhibited universality across different pollutants. Overall, this study presents a novel and useful strategy to convert solar energy into chemical energy through efficient H 2 O 2 production and provides an effective alternative for the degradation of emerging pollutants.