MoS2-based hetero-nanostructures for photocatalytic, photoelectrocatalytic and piezocatalytic remediation of hazardous pharmaceuticals

Recent increase in the global consumption of pharmaceutical compounds has enhanced the economic burden for the human population and increased the accumulation of these pharmaceutical compounds in the environment via wastewater released from treatment plants to various water bodies, such as groundwater and surface water, which poses a severe threat to human health as well as aquatic and terrestrial life. Several conventional treatment techniques available to remove industrial pharmaceutical-active compounds (PACs), such as ozonation, photolysis, photocatalysis, and wetland treatment, for the remediation of wastewater resources. Owing to their unique physicochemical features, natural abundance, and the ability to substitute noble metal catalysts, MoS2-based hetero-nanostructured materials have attracted significant interest. This study provides a brief overview of the recent research on the structural properties and synthesis of MoS2-based heterojunctions, i.e., traditional type-II, all-solid-state, direct Z-scheme and S-scheme heterojunction photocatalytic systems. The layered 2D structure of MoS2-based materials contributes to the high mobility of the photoinduced charge carriers, which makes photodegradation rapid and highly stable. These innovative materials have high surface area, small size, photosensitivity, tunable pore size, and electrochemical and magnetic properties. The large-scale application of MoS2 as a single semiconductor material remains limited. Essentially, a mechanistic investigation on the separation of photoinduced charge carriers and possible approaches to improve the photooxidative potential of MoS2 with a maximum recovery rate are needed. Moreover, piezocatalytic route for remediation of the hazardous pharmaceutical is addressed. Finally, a brief, conclusive remark regarding current studies and the unresolved challenges of MoS2-based photocatalysts addressing future research.