Semiconductor heterojunction configurations for photoelectrochemical degradation of organic pollutants in water

Abstract The rapid growth of research into semiconductor heterojunctions for photoelectrochemical (PEC) degradation of organic contaminants has revealed a significant knowledge gap; the inability to link the relationships between atomic scale properties, such as surface morphology, and charge carrier dynamics to overall PEC degradation efficiency, thus hindering rational design of materials. This review therefore discusses charge transfer mechanisms, interface engineering methods, and the influence of material properties in a semiconductor heterojunction to give a systematic basis of design of PEC materials. Semiconductor heterojunctions are formed by the combination of two semiconductors with different energy levels to enhance the charge separation efficiency and to minimize the recombination of photogenerated electron-hole pairs. These structures operate based on the utilization of built-in electric fields at the heterojunction interface that in turn increases redox activity thus facilitating the degradation of organic contaminants. Based on the combination of experimental and theoretical findings, this review examines the design and role of semiconductor heterojunctions, providing an overview of their application in PEC degradation of water contaminants.