Enhanced photoelectrochemical water splitting performance of α-Fe2O3 nanostructures modified with Sb2S3 and cobalt phosphate

In this paper, α-Fe2O3 photoanodes with different morphologies have been prepared on FTO by hydrothermal method. The α-Fe2O3/Sb2S3 heterojunction and α-Fe2O3/Sb2S3/Co-Pi nanocomposites are firstly developed as photoanodes applied in photoelectrochemical (PEC) water splitting, which possesses low onset potential and high photocurrent density. In detail, α-Fe2O3 films with morphologies of nanoparticals and nanorods have been compared and the morphological effect on the photoelectrocatalytic activity has been discussed. To mitigate the limitation of charge recombination of pure α-Fe2O3, the antimony sulfide (Sb2S3) and cobalt-phosphate (Co-Pi) are subsequently incorporated onto α-Fe2O3 with different morphologies. Among them, α-Fe2O3/Sb2S3/Co-Pi photoelectrocatalyst based on α-Fe2O3 nanorods achieved a high photocurrent of 1.14 mA cm−2 at 1.23 V vs RHE and a low onset potential of 0.8 V vs. RHE as compared to those of other photoanodes. The superior PEC behaviors benefit from the improved charge separation and transfer efficiency caused by the modification of Sb2S3 due to the better visible response and the appropriate CB/VB designs as well as the coupling with Co-Pi that provides an alternative pathway for water splitting. This work emphasizes that composite photoanode strategies provide a conceptual blueprint to develop sustainable, environmental, and efficient photoelectrodes for solar-driven photoelectrochemical water splitting.