Continuous photocatalysis via Z-scheme based nanocatalyst system for environmental remediation of pharmaceutically active compound: Modification, reaction site, defect engineering and challenges on the nanocatalyst

Abstract

Photocatalysis is the process of exploitation of solar radiation for the creation of a pollution-free stable environment. Photocatalysis has applications in various fields including toxic pollutant degradation, heavy metal reduction, clean energy production (hydrogen generation by water splitting), and CO2 reduction. Conventional photocatalyst has various shortcomings including poor visible light harvesting and faster charge recombination. The construction of Z-scheme heterojunctions can overcome these shortcomings and solve both the energy crisis and environmental degradation at once. This review is discussed based on the material aspects where interfacial charge transfer and internal electric field play a crucial role in the overall efficiency of a photocatalytic system. Firstly, semiconductors' redox potential and band gap are summarized as they are the key factor in photocatalysis. The charge transfer mechanism such as internal electric field and interfacial defects has been discussed to understand the material design of Z-scheme. Various semiconductor nanoparticles have been used for the construction of the Z-scheme, which has been compared and discussed extensively based on their effectiveness. This review intends to provide up-to-date works in Z-scheme, to guide future developments for better performance and maximum efficiency.