Surface Plasmon Resonance Effect of Noble Metal Nanoparticles on BiVO[sub.4] for Photoelectrochemical Water Splitting

• Published in: Inorganics 2023-05, Vol.11 (5)
• Main Authors: Liu, Rui, Zhan, Difu, Wang, Dong, Han, Changcun, Fu, Qian, Zhu, Hongxun, Mao, Zhuxiang, Liu, Zhao-Qing
• Format: Article
• Language: English
• Subjects: Analysis; Bismuth; Chemical properties; Electric properties; Gold; Mechanical properties; Nanoparticles; Optical properties; Silver; Surface plasmon resonance; Vanadates
• ISSN: 2304-6740
• DOI: 10.3390/inorganics11050206

Photoelectrochemical (PEC) splitting water technology over the years has gradually matured, and now photoanodes loaded with nanoparticles (NPs) show excellent PEC performance. Each of the metal NPs has a different effect on the PEC performance of BiVO[sub.4] . This work selected the noble metals Ag and Au to modify BiVO[sub.4] and study its PEC performance. After recombination, the photocurrent densities of Ag/BiVO[sub.4] and Au/BiVO[sub.4] photoanodes were 3.88 mA/cm[sup.2] and 1.61 mA/cm[sup.2] at 1.23 V[sub.RHE] , which were 3.82 and 1.72 times that of pure BiVO[sub.4] . The hydrogen evolution of pure BiVO[sub.4] is about 1.10 μmol·cm[sup.−2] . Ag/BiVO[sub.4] and Au/BiVO[sub.4] contain 3.56 and 2.32 times pure BiVO[sub.4] , respectively. Through the research, it was found that the composite noble metal (NM) NPs could improve the PEC properties; this is because NM NPs can introduce a surface plasmon resonance (SPR) effect to increase the concentration and accelerate the separation of carriers. The mechanism of the SPR effect can be explained as NM NPs are excited by light generating “hot electrons”, and the hot electrons can directly enter the conduction band (CB) of BiVO[sub.4] through an electron transfer mechanism. The potential energy of the Schottky barrier generated by the contact of NM NPs with BiVO[sub.4] is smaller than that generated by the SPR effect, which enables the “hot electrons” to be smoothly transferred from the NM NPs to the conduction band of BiVO[sub.4] without returning to the NM NPs. Ag/BiVO[sub.4] showed higher PEC activity than Au/BiVO[sub.4] because of its higher light absorption, photocurrent, and oxygen evolution capacity. It can be seen that loading NM NPs increases the concentration of the carriers while the separation and transfer rates of the carriers are improved. In conclusion, it was concluded from this study that the loading of NM NPs is an effective method to improve the water oxidation kinetics of BiVO[sub.4] photoanodes.