Cu 2 O nanoparticles sensitize TiO 2 /CdS nanowire arrays to prolong charge carrier lifetime and highly enhance unassisted photoelectrochemical hydrogen generation with 4.3% efficiency

• Published in: Dalton transactions : an international journal of inorganic chemistry 2020-07, Vol.49 (27), p.9282-9293
• Main Authors: Jiang, Kangbo, Wang, Wenzhong, Wang, Jun, Zhu, Tianyu, Yao, Lizhen, Cheng, Ying, Wang, Yue, Liang, Yujie, Fu, Junli
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/D0DT01643H

Effective separation of charge carriers and substantial prolongation of charge carrier lifetime are two vital issues for a photoanode to achieve highly efficient photoelectrochemical (PEC) hydrogen generation. Herein, a Cu 2 O-nanoparticle-sensitized TiO 2 /CdS (TiO 2 /CdS/Cu 2 O) nanowire array photoanode is fabricated via subtly combining successive ionic layer adsorption and reaction with a chemical bath deposition method. Both the type-II band alignment with a stair-like structure and a p–n junction are integrated into this ternary photoanode. The fabricated photoanode shows a significant enhancement in the PEC H 2 production with 4.3% efficiency. The measurements of light absorption, photoluminescence and electrochemical spectra undoubtedly demonstrate that the enhanced PEC H 2 generation is ascribed to the remarkable enhancement of visible-light absorbing ability, efficient space charge separation and substantial prolongation of charge carrier lifetime, which are achieved by the synergetic effects of the type-II band alignment with a stair-like structure and the p–n junction. The enhanced PEC H 2 generation demonstrates the potential of the TiO 2 /CdS/Cu 2 O nanowire arrays as a photoanode to efficiently convert solar energy into chemical fuels.