Photocatalytic oxidation of pollutants in gas-phase via Ag₃PO₄-based semiconductor photocatalysts: Recent progress, new trends, and future perspectives

Abstract

Air pollution has become a significant challenge for both developing and developed nations. due to its close association with numerous fatal diseases such as cancer, respiratory, heart attack, and brain stroke. Over recent years, heterogeneous semiconductor photocatalysis has emerged as an effective approach to air remediation due to the ease of scale-up, ready application in the field, use of solar light and ready availability of a number of different effective photocatalysts. To date, most work in this area has been conducted using UV-absorbing photocatalysts, such as TiO₂ and ZnO; However, recent studies have revealed Ag₃PO₄ as an attractive, visible-light-absorbing alternative, with a bandgap of 2.43 eV. In particular, this material has been shown to be an excellent photocatalyst for the removal of many types of pollutants in the gas phase. However, the widespread application of Ag₃PO₄ is restricted due to its tendency to undergo photoanodic corrosion and the poor reducing power of its photogenerated conductance band electrons, which are unable to reduce O₂ to superoxide •O₂⁻. These limitations are critically evaluated in this review. In addition, recent studies on the modification of Ag₃PO₄ via combination with the conventional heterojunctions or Z-scheme junctions, as well as the photocatalytic mechanistic pathways for enhanced gas-pollutants removal, are summarized and discussed. Finally, an overview is given on the future developments that are required in order to overcome these challenges and so stimulate further research into this promising field.

Graphical abstract

Keywords:

• Ag₃PO₄
• conventional heterojunctions
• gaseous pollutants
• photocatalytic oxidation process
• Z‐scheme junctions

Additional information

Funding

This work was supported by the Ibn Zohr University (Morocco).