Preparation of Sb2O3/Sb2S3/FeOOH composite photoanodes for enhanced photoelectrochemical water oxidation

A novel Sb 2 O 3 /Sb 2 S 3 /FeOOH photoanode was fabricated via a simple solution impregnation method along with chemical bath deposition and post-sulfidation. The X-ray diffractometry, Raman measurement, and X-ray photoelectron spectroscopy show that the Sb 2 O 3 /Sb 2 S 3 /FeOOH thin films are successfully prepared. SEM−EDS analyses reveal that the surface of Sb 2 O 3 /Sb 2 S 3 thin films becomes rough after the immersion in the FeCl 3 solution. The optimized impregnation time is found to be 8 h. The FeOOH co-catalyst loaded Sb 2 O 3 /Sb 2 S 3 electrode exhibits an enhanced photocurrent density of 0.45 mA/cm 2 at 1.23 V versus RHE under simulated 1 sun, which is approximately 1.41 times compared to the photocurrent density of the unloaded one. Through the further tests of UV−Vis spectroscopy, the electrochemical impedance spectra, and the PEC measurements, the enhancement can result from the increased light-harvesting ability, the decreased interface transmission impedance, and the remarkably enhanced carrier injection efficiency.