Nickel carrier transfer bridge for improved photocatalytic water splitting of Zn2GeO4
Ruiqing Zou, Sibi Liu, Jie Su, Wei Ding, Y. Wang, Fei Yan, Peng Guo, Junchao Zhou, Youzi Zhang, Xuanhua Li
Abstract
Photocatalytic water splitting can convert solar energy into hydrogen, which has important implications for reducing dependence on fossil fuels. Constructing heterojunctions is a universal method for facilitating charge transfer, but the poor interface matching limits its charge separation and photocatalytic activity. Here, a metal-nickel bridging (nickel interlayer) NiO-Ni-Zn 2 GeO 4 photocatalyst with well interface matching is designed through a partial oxidation strategy. Structure and in situ Raman characterization demonstrate that the nickel interlayer substantially optimizes interface matching and causes the first-order phonon mode transfer from the first-order longitudinal wave to the first-order transverse wave, which implies that NiO acts as the site for hydrogen production and violent surface reaction. Therefore, the nickel interlayer provides a charge transfer channel for carrier separation. Meanwhile, density functional theory calculations prove an optimal hydrogen-oxygen bond-breaking process with 36 % barriers decrease obtained via the effect of nickel interlayer. As a result, NiO-Ni-Zn 2 GeO 4 shows the photocatalytic hydrogen production rate of 206.6 μmol g −1 h −1 , which is over 8 times greater than that of Zn 2 GeO 4 . This study offers a new approach for designing heterojunctions with well-matched interface and efficient charge separation.