Boosting BiVO ₄ Photoanode With Sulfur Doped Carbon Quantum Dots for Efficient Solar‐Driven Water Oxidation

ABSTRACT With the in‐depth research on efficient hole‐transport materials in the field of photoelectrochemical (PEC) water splitting, their rational integration with photoanodes is crucial for enhancing solar energy conversion efficiency. This study reports the loading of sulfur doped carbon quantum dots (S‐CQD) as a hole transport layer onto a BiVO 4 photoanode. The results indicates that the S‐CQD effectively promotes hole extraction and transport from BiVO 4 , the optimized BiVO 4 /S‐CQD composite photoanode achieves a photocurrent density of 1.66 mA cm −2 (1.23 V RHE ), corresponding to 1.71 times that of pristine BiVO 4 photoanode. Furthermore, the surface‐deposited FeOOH accelerates water oxidation kinetics, the optimized BiVO 4 /S‐CQD/FeOOH composite photoanode achieves a photocurrent density of 2.88 mA cm −2 (1.23 V RHE ), which is 2.96 times that of pristine BiVO 4 . This work provides an effective quantum dot‐based strategy for designing high‐performance BiVO 4 photoanodes.