Characterization of semiconductor photocatalysts

The long-standing popularity of semiconductor photocatalysis due to its great potential in a variety of applications has resulted in the creation of numerous semiconductor photocatalysts, which stimulated the development of various characterization methods. This review aims to summarize the main characterization methods for assessing the most important properties of semiconductor photocatalysts, including their chemical composition (elemental composition, and chemical state/structure), physical properties (physical structure, crystallographic properties, optical absorption, charge dynamics, defects, and colloidal and thermal stability), and band structure (band gap, band edges/band edge offsets, and Fermi level). The discussion on each of these methods starts with a concise presentation of its fundamentals followed by carefully selected examples. At the end, a chart correlating the properties of a semiconductor with its potential characterization methods as well as outlook are provided. Overall, the aim of this review article is to help materials chemists and physicists, particularly students, in selecting suitable techniques for the characterization of semiconductor photocatalysts and potentially other relevant materials.