Semiconductors Application Forms and Doping Benefits to Wastewater Treatment: A Comparison of TiO<sub>2</sub>, WO<sub>3</sub>, and g-C<sub>3</sub>N<sub>4</sub>

oleh: Eryk Fernandes, João Gomes, Rui C. Martins

Format: Article
Diterbitkan: MDPI AG 2022-10-01

Deskripsi

Photocatalysis has been vastly applied for the removal of contaminants of emerging concern (CECs) and other micropollutants, with the aim of future water reclamation. As a process based upon photon irradiation, materials that may be activated through natural light sources are highly pursued, to facilitate their application and reduce costs. TiO<sub>2</sub> is a reference material, and it has been greatly optimized. However, in its typical configuration, it is known to be mainly active under ultraviolet radiation. Thus, multiple alternative visible light driven (VLD) materials have been intensively studied recently. WO<sub>3</sub> and g-C<sub>3</sub>N<sub>4</sub> are currently attractive VLD catalysts, with WO<sub>3</sub> possessing similarities with TiO<sub>2</sub> as a metal oxide, allowing correlations between the knowledge regarding the reference catalyst, and g-C<sub>3</sub>N<sub>4</sub> having an interesting and distinct non-metallic polymeric structure with the benefit of easy production. In this review, recent developments towards CECs degradation in TiO<sub>2</sub> based photocatalysis are discussed, as reference catalyst, alongside the selected alternative materials, WO<sub>3</sub> and g-C<sub>3</sub>N<sub>4</sub>. The aim here is to evaluate the different techniques more commonly explored to enhance catalyst photo-activity, specifically doping with multiple elements and the formation of composite materials. Moreover, the possible combination of photocatalysis and ozonation is also explored, as a promising route to potentialize their individual efficiencies and overcome typical drawbacks.