Remarkably Enhanced Hydrogen Generation of Organolead Halide Perovskites via Piezocatalysis and Photocatalysis

• Published in: Advanced energy materials 2019-10, Vol.9 (37), p.n/a
• Main Authors: Wang, Mengye, Zuo, Yunpeng, Wang, Jingli, Wang, Yi, Shen, Xinpeng, Qiu, Bocheng, Cai, Lejuan, Zhou, Feichi, Lau, Shu Ping, Chai, Yang
• Format: Article
• Language: English
• Subjects: CH3NH3PbI3 perovskite; Conduction bands; Crystal structure; Current carriers; Electric fields; Fossil fuels; Hydrogen; Hydrogen evolution; hydrogen generation; Hydrogen production; Light; Nanomaterials; Perovskites; Photocatalysis; Piezoelectricity; piezoelectrics; piezophotocatalysis
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201901801

To alleviate photoinduced charge recombination in semiconducting nanomaterials represents an important endeavor toward high‐efficiency photocatalysis. Here a judicious integration of piezoelectric and photocatalytic properties of organolead halide perovskite CH3NH3PbI3 (MAPbI3) to enable a piezophotocatalytic activity under simultaneous ultrasonication and visible light illumination for markedly enhanced photocatalytic hydrogen generation of MAPbI3 is reported. The conduction band minimum of MAPbI3 is higher than hydrogen generation potential (0.046 V vs normal hydrogen electrode), thereby rendering efficient hydrogen evolution. In addition, the noncentrosymmetric crystal structure of MAPbI3 enables its piezoelectric properties. Thus, MAPbI3 readily responds to external mechanical force, creating a built‐in electric field for collective piezophotocatalysis as a result of effective separation of photogenerated charge carriers. The experimental results show that MAPbI3 powders exhibit superior piezophotocatalytic hydrogen generation rate (23.30 µmol h−1) in hydroiodic acid (HI) solution upon concurrent light and mechanical stimulations, much higher than that of piezocatalytic (i.e., 2.21 µmol h−1) and photocatalytic (i.e., 3.42 µmol h−1) hydrogen evolution rate as well as their sum (i.e., 5.63 µmol h−1). The piezophotocatalytic strategy provides a new way to control the recombination of photoinduced charge carriers by cooperatively capitalizing on piezocatalysis and photocatalysis of organolead halide perovskites to yield highly efficient piezophotocatalysis. CH3NH3PbI3 exhibits a superior piezophotocatalytic hydrogen generation rate upon concurrent light and mechanical stimulations, much higher than that of piezocatalytic and photocatalytic hydrogen evolution rate as well as their sum. Combining piezocatalysis and photocatalysis of semiconductor photocatalysts to attain a collective piezophotocatalysis may represent an appealing strategy for efficient solar energy conversion, including water splitting, organic fuel production, etc.