Covalent S-O Bonding Enables Enhanced Photoelectrochemical Performance of Cu2S/Fe2O3 Heterojunction for Water Splitting

The severe charge recombination and the sluggish kinetic for oxygen evolution reaction have largely limited the application of hematite (alpha-Fe2O3) for water splitting. Herein, the construction of Cu2S/Fe2O3 heterojunction and discover that the formation of covalent S-O bonds between Cu2S and Fe2O3 can significantly improve the photoelectrochemical performance and stability for water splitting is reported. Compared with bare Fe2O3, the heterostructure of Cu2S/Fe2O3 endows the resulting electrode with enhanced charge separation and transfer, extended range for light absorption, and reduced charge recombination rate. Additionally, due to the photothermal properties of Cu2S, the heterostructure exhibits locally a higher temperature under illumination, profitable for increasing the rate of oxygen evolution reaction. Consequently, the photocurrent density of the heterostructure is enhanced by 177% to be 1.19 mA cm(-2) at 1.23 V versus reversible hydrogen electrode. This work may provide guideline for future in the design and fabrication of highly efficient photoelectrodes for various reactions.

Automated summary

The construction of Cu2S/Fe2O3 heterojunction can significantly improve the photoelectrochemical performance and stability for water splitting, enhancing charge separation and transfer, extending light absorption range, and reducing charge recombination rate. Additionally, the heterostructure exhibits a higher temperature under illumination due to the photothermal properties of Cu2S, which is beneficial for increasing the rate of oxygen evolution reaction.