Zinc selenide engineered nanostructures: insights into modification strategies, and multifunctional applications in environmental remediation, gas sensing, energy storage, and antimicrobial activity.

Zinc selenide (ZnSe), an outstanding and admirable photocatalytic material from the II-VI group, exhibits a direct energy band gap of 2.67 eV. This rising contender has sparked considerable attention owing to its distinctive physicochemical characteristics and extensive multifunctional potential. This article commences with a comprehensive and systematic exploration of the intrinsic novel attributes of ZnSe nanostructures, encompassing their structural, optical, and electronic novelties. It further summarizes the various fabrication methodologies which have been instrumental in tailoring parameters like particle size, morphology, and crystallinity to optimize functional performance across a breadth of applications. Key modification strategies, including elemental doping and heterojunction engineering, are highlighted to underscore their indispensable roles in mitigating the recombination rate while enhancing the efficiency of photoinduced charge carrier separation and migration. The discourse progresses to delineate the evolution from conventional composite architectures to advanced Z-scheme configurations, offering profound insights into their revolutionary implications. Additionally, essential characterization techniques are surveyed, elucidating the intricate correlations between structural, morphological, optical, and electronic properties and their resultant influence on functional efficacy. Furthermore, the study spotlights the recent advancements in multifaceted applications in utilizing ZnSe-based composites as potential tools for environmental applications, including the removal of hazardous heavy metals, pharmaceuticals, phenolic compounds, and other persistent organic contaminants, as well as their role in CO2 mitigation, Cr(vi) remediation, gas sensing, advanced electrode materials in lithium-ion (LIBs), sodium-ion (SIBs), and potassium-ion batteries (PIBs), alongside antimicrobial activities. Mechanistic insights into these remediation pathways are thoroughly outlined. Subsequently, the article sketches the inherent challenges and delineates future research developments and potential avenues for material optimization, which is anticipated to facilitate further exploration and innovation in this dynamic field in the days to come.