Issue 5, 2022, Issue in Progress

Characterization of Cu2O/CuO heterostructure photocathode by tailoring CuO thickness for photoelectrochemical water splitting

Abstract

Cu2O/CuO heterostructure is a well-known strategy to improve the performance of Cu2O photocathodes for photoelectrochemical (PEC) water splitting. The CuO thickness in the Cu2O/CuO heterostructure is considered as a critical factor affecting the PEC performance because it is highly related to the light utilization and charge separation/transport. In this study, the Cu2O/CuO photocathode tailoring the CuO thickness was investigated to examine the CuO thickness influence on the PEC performance. Cu2O/CuO photocathodes were prepared by the electrodeposition and subsequent thermal annealing process and the Cu2O/CuO heterostructure was controlled by the annealing temperature and time. It was demonstrated that the increased CuO thickness enhances the light absorption in the long wavelength region and improves the charge separation by the reinforced band bending. However, the thick CuO hinders the efficient charge transport in the Cu2O/CuO heterostructure, resulting in the decreased PEC performance. Therefore, it is necessary to optimize the CuO thickness for the enhanced PEC performance of Cu2O/CuO photocathodes. Consequently, the Cu2O/CuO photocathode consisting of the similar CuO thickness with its minority carrier diffusion length (∼90 nm) was fabricated by annealing at 350 °C for 20 min, and it shows the optimal PEC performance (−1.2 mA cm−2 at 0 V vs. RHE) in pH 6.5 aqueous solution, resulting from the enhanced light utilization and the reinforced band bending.

Graphical abstract: Characterization of Cu2O/CuO heterostructure photocathode by tailoring CuO thickness for photoelectrochemical water splitting

Supplementary files

Article information

Article type
Paper
Submitted
06 Dec 2021
Accepted
13 Jan 2022
First published
20 Jan 2022
This article is Open Access
Creative Commons BY license

RSC Adv., 2022,12, 2632-2640

Characterization of Cu2O/CuO heterostructure photocathode by tailoring CuO thickness for photoelectrochemical water splitting

D. Jeong, W. Jo, J. Jeong, T. Kim, S. Han, M. Son and H. Jung, RSC Adv., 2022, 12, 2632 DOI: 10.1039/D1RA08863G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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