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. [Display omitted] • Compared with other electrodes, CQDs + Ni(OH) 2 /BiVO 4 showed the largest photocurrent. • The joint effect of CQDs and Ni(OH) 2 enhances the charge injection efficiency. • CQDs and Ni(OH) 2 jointly reduce the surface charge recombination. • Ni(OH) 2 combined CQDs improve the migration of photogenerated electrons and holes. • The stability of CQDs + Ni(OH) 2 /BiVO 4 is far superior to that of other electrodes. [ABSTRACT FROM AUTHOR]