Decorating Cu2O with Ni-doped metal organic frameworks as efficient photocathodes for solar water splitting

• Published in: International journal of hydrogen energy Vol. 48; no. 45; pp. 17065 - 17073
• Main Authors: Yu, Run, Chen, Qianqiao, Li, Wenhua, Yu, Xinyuan, Zhong, Qin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 26.05.2023
• Subjects: Cu2O; MOFs; Ni-doped; PEC water Splitting; Photocathode; PEC water Splitting; MOFs; Ni-doped; Photocathode; Cu2O
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2023.01.145

Severe photocorrosion and fast photoexcited charges recombination hinder the application of Cu2O in photoelectrochemical (PEC) water splitting. In this work, Ni-doped metal-organic frameworks is firstly applied to improve the performance of electrodeposited Cu2O. A decorative layer of Ni-doped Cu3(BTC)2 (Ni-CuBTC) was in-suit constructed on Cu2O through solvothermal followed by ion-exchange. Cu2O/Ni-CuBTC photocathodes increase absorption edge to ∼800 nm, positive shift flat band position to 0.4 V, and decrease Tafel value to 74 mV/dec. These results confirm the decorative layer can extend light absorption, facilitate photoexcited charge separation and transfer, and enhance HER activity. A photocurrent density of −1.51 mA/cm2 at 0 VRHE is obtained with the decoration of Ni-CuBTC, which is 3.4 times of pristine Cu2O photocathode. Here, the PEC water splitting performance of electrodeposited Cu2O has been significantly improved with noble-metal-free decorations, which provides a new idea for solving the defects of Cu2O based photocathode. [Display omitted] •Ni-CuBTC decorated Cu2O as HER photocathode by solvothermal and ion-exchange.•CuBTC can adjust the energy band structure and promote charges transfer.•HER kinetics can be improved with Ni doping.•Noble-metal-free Ni-CuBTC acts as co-catalyst, photosensitizer, and protector.•It exhibits 3.4 times current density of bare Cu2O with −1.51 mA/cm2 at 0 VRHE.