Enhancing photoelectrochemical water oxidation activity of BiVO4 photoanode through the Co-catalytic effect of Ni(OH)2 and carbon quantum dots

The CQDs  + Ni(OH) 2 /BiVO 4 photoanode was fabricated by introducing CQDs with fluorescence and optical properties . The CQDs + Ni(OH) 2 /BiVO 4 photoanode exhibited a low water oxidation onset potential (∼0.2 V vs. RHE) and a photocurrent density of 3.05 mA cm −2 at a voltage of 1.23 V vs. RHE, which is about 2.5 times than that of the unmodified BiVO 4 electrode, and the charge injection efficiency is 65%. Surface dynamics test showed that CQDs + Ni(OH) 2 /BiVO 4 photoanode had higher charge transfer rate and lower charge recombination rate than BiVO 4 electrode. As a cheap and stable catalyst for water oxidation, Ni(OH) 2 combined with CQDs can effectively improve the migration of photogenerated electrons and holes, thereby improving the photoelectrochemical (PEC) water oxidation activity of the photoanode.