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

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 Cu-3(BTC)(2) (Ni-CuBTC) was in-suit constructed on Cu2O through solvothermal followed by ion-exchange. Cu2O/Ni-CuBTC photocathodes increase absorption edge to similar 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/cm(2) 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. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Ni-doped metal-organic frameworks are applied to improve the performance of electrodeposited Cu2O, enhancing light absorption, charge separation and transfer, and HER activity.