Effect of Phase Junction Structure on the Photocatalytic Performance in Overall Water Splitting: Ga2O3 Photocatalyst as an Example

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• 作者：Shaoqing Jin ; Xiang Wang ; Xiuli Wang ; Minggang Ju ; Shuai Shen ; Wanzhen Liang ; Yi Zhao ; Zhaochi Feng ; Helen Y. Playford ; Richard I. Walton ; Can Li
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 13, 2015
• 年：2015
• 卷：119
• 期：32
• 页码：18221-18228
• 全文大小：547K
• ISSN：1932-7455

文摘

The fabrication of surface phase junctions has proven to be an efficient strategy for the enhancement of photocatalytic activity; however, some questions about these systems are not yet well understood. In this study, the photocatalytic overall water splitting reaction was achieved on photocatalysts with pure and mixed phase compositions of cubic 纬-Ga₂O₃ and monoclinic 尾-Ga₂O₃. All the Ga₂O₃ photocatalysts can split water stoichiometrically into H₂ and O₂; however, the phase-mixed 纬/尾-Ga₂O₃ photocatalyst with a small amount of 尾 phase shows the lowest activity. This is opposite from that of the reported 伪/尾-Ga₂O₃ system in which the phase-mixed 伪/尾-Ga₂O₃ photocatalyst with a small amount of 尾 phase shows much higher photocatalytic activity than the individual phases. Much more disordered structure is found between the 纬 and 尾 phases in the 纬/尾-Ga₂O₃ photocatalyst with low content of 尾 phase due to the defective spinel structure of 纬 phase. Spectroscopic characterization and theoretical calculations indicate that the disordered structure serves as defect and charge recombination centers resulting in the decrease of photocatalytic activity. Based on the analysis of 伪/尾-Ga₂O₃ and 纬/尾-Ga₂O₃ systems, it is proposed that a prerequisite for the formation of phase junction boosting photocatalytic reactions is that the interfacial structure between two phases should not be disordered or defective.