Novel WO3/Sb2S3 Heterojunction Photocatalyst Based on WO3 of Different Morphologies for Enhanced Efficiency in Photoelectrochemical Water Splitting

We report the fabrication of tungsten trioxide (WO3) with different morphologies applied in photoelectrochemical (PEC) water splitting. The antimony sulfide (Sb2S3) was incorporated onto WO3 for the first time with the aim of improving its photoelectrocatalytic activity under visible-light illumination. In the present work, WO3 of different morphologies were fabricated on FTO glass via adjusting the pH value via a facile hydrothermal method and the morphological effect on the photoelectrocatalytic activity of the obtained samples has been discussed. WO3/Sb2S3 heterojunction photoelectrocatalysts were subsequently synthesized successfully to further improve the photoelectrocatalytic activity. Among them, WO3/Sb2S3 heterojunction photoelectrocatalyst based on WO3 micro crystals achieved an enhanced photocurrent of 1.79 mA/cm2 at 0.8 V versus RHE under simulated sunlight, compared to 0.45 mA/cm2 of pristine WO3 micro crystals. This excellent PEC performance benefits from the enhanced light absorbance, construction of suitable energy band gap, the improved photogenerated electron–hole pairs separation and transfer efficiency, which potentially provides new insights into PEC water splitting systems.