Modulation of charge-transfer behavior adaptive interface treatment for efficient photoelectrochemical water splitting

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2024-03, Vol.12 (11), p.645-6411
• Main Authors: Quan, Jingjing, Wang, Jing, Hai, Kunlin, Ning, Xingming, Chen, Xinbing
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta07597d

The integration of a transition metal hydroxide (TMH) and semiconductor (SC) is a promising approach for improving photoelectrochemical (PEC) water oxidation. However, charge recombination at the SC/TMH interface is inevitable. Herein, a desirable charge-separation system was obtained through a simple acid-etching strategy ( i.e. , hydrochloric acid, HA) in the SC/TMH coupling system. Optimized BiVO 4 -HA/FeNi(OH) X exhibited a photocurrent density of 4.7 mA cm −2 at 1.23 V versus the reversible hydrogen electrode (RHE), which was 4.4-times higher than that of pure BiVO 4 and 1.8-times higher than that of BiVO 4 /FeNi(OH) X , respectively. Systematic studies revealed that a considerably enhanced photocurrent could be determined by three main factors: (1) formation of an adaptive interface by enhanced hydrophilicity boosted hole-transfer kinetics and suppressed interface recombination; (2) reducing the density of surface states; (3) the shortened distance of the hole from the bulk to the surface. Importantly, this strategy could be extended to other TMH (CoNi(OH) X and CoFe(OH) X ), showing its universality. This work opens up opportunities in interfacial engineering of SC/TMH systems for efficient PEC water splitting. We report a "one stone, three birds" strategy for efficiently suppressing the electron-hole recombination occurring at the SC/TMH interface. After acid treatment, optimized BV-HA/FeNi(OH) X photoanodes showed enhanced photocurrent density and excellent photostability.