Role of interfacial AuNPs in solid-state direct Z-scheme MoS2/Au/g-C3N4 heterojunction nanocomposite’s pollutant degradation activity under sunlight

Abstract

Constructing the semiconductor heterojunction photocatalyst is the most promising method for environmental pollutant degradation. In this work, solid-state direct z-scheme MoS2/Au/g-C3N4 heterojunction nanocomposites with different percentages of MoS2 (2%, 4%, and 6%) were successfully prepared by hydrothermal and impregnation processes. Under sunlight irradiation, this direct z-scheme heterojunction nanocomposites act as an efficient photocatalyst for the degradation of Methylene blue (MB) and 2, 4-Dicholorophenol (2, 4-DCP) in 60 min. The gold nanoparticles (AuNPs) were deposited on the surface of g-C3N4 was confirmed by TEM analysis. The highest photocatalytic activity of 6%MoS2/Au/g-C3N4 exhibited 100% degradation of MB (10 mg/L) within 60 min. A significant improvement in degradation activity was obtained by the efficient separation and transfer of photogenerated charge carriers. Also, radical trapping analysis and EPR results confirmed that the O2•– plays an important role in MB degradation. Similarly, the 2, 4-DCP herbicide was found to be degraded (40%) within 60 min. These findings demonstrate that depending on the loading quantity of MoS2, the MoS2/Au/g-C3N4 nanocomposites exhibit increased photocatalytic activity for the degradation of these pollutants in comparison to bare g-C3N4.