Integrating Mixed Halide Perovskite Photocatalytic HI Splitting and Electrocatalysis into a Loop for Efficient and Robust Pure Water Splitting
Xiaolei Liu, Qianqian Zhang, Shengli Zhao, Zeyan Wang, Yuanyuan Liu, Zhaoke Zheng, Hefeng Cheng, Ying Dai, Baibiao Huang, Peng Wang
Abstract
Abstract Developing a hydrogen economy to replace traditional fossil fuels is essential for sustainable human development. As two promising H 2 production strategies, photocatalytic and electrocatalytic water splitting with large reaction energy barriers still face the great challenges of poor solar‐to‐hydrogen efficiency and large electrochemical overpotentials, respectively. Herein, a new strategy is proposed to disassemble the difficult pure water splitting into two parts that are easy to implement, namely mixed halide perovskite photocatalytic HI splitting for H 2 production, and simultaneous electrocatalytic I 3 − reduction and O 2 production. The efficient charge separation, abundant H 2 production active sites, and a small HI splitting energy barrier contribute to the superior photocatalytic H 2 production activity of MoSe 2 /MAPbBr 3− x I x (CH 3 NH 3 + = MA). Subsequent electrocatalytic I 3 − reduction and O 2 production reactions only need a small voltage of 0.92 V to drive, which is far lower than that of the electrocatalytic pure water splitting (>1.23 V). The molar ratio of H 2 (6.99 mmol g −1 ) to O 2 (3.09 mmol g −1 ) produced during the first photocatalytic and electrocatalytic cycle is close to 2:1, and the continuous circulation of I 3 − /I − between the photocatalytic and electrocatalytic systems can achieve efficient and robust pure water splitting.