Transient absorption spectroscopy insights into heterogeneous photocatalysis for water pollution remediation

Transient absorption studies have contributed to our current understanding of heterogeneous photocatalytic systems. Insights have been gained into the nature of the photogenerated charge carriers and their trapping, their subsequent transfer to the reaction medium, the transformations and kinetics that ensue from transient species to the final reaction products, and equally important the time scales at which these events occur. In this review, the focus is on learnings relevant to heterogeneous photocatalytic systems for water pollution remediation. It is subdivided into sections on TAS studies of heterogeneous photocatalysis for: Dye degradation (Section 2.0); Organic pollutant degradation (Section 3.0); and Inorganic pollutants removal (Section 4.0). The majority of the studies has been on heterogenous TiO2 photocatalysis, but more recently novel photocatalytic materials such as doped and heterostructured materials have also been studied. Those latter systems have great potential for the development of solar driven heterogeneous photocatalysis for environmental remediation.