Design and development of symmetric aromatic bischalcogenide-based photocatalysts for water treatment application: a concise study of diphenyl diselenide polypyrrole nanocatalysis

Abstract

Dopant engineering can be a very selective approach in designing hybrid materials. Incorporating the required functionality in a dopant effectively modulates its properties towards aimed applications. Consequently, this work through a comparative study envisaged the incorporation of chalcogenides (S, Se, and Te) in a biphenyl motif based on the analysis of major photocatalytic descriptors. Bischalcogenides as tuned dopants have been impressive in enhancing the surface area, increasing crystallinity and facilitating band gap shifts towards better light harvesting. In addition, the chalcogen effect was observed to induce preferential ion migration, leading to effective charge separation and attenuated recombination rates. Photocatalytic descriptors evaluated from electrochemical impedance spectroscopy and photoluminescence data corroborated the chalcogen effect in the observed trend (Ph)₂ < (PhS)₂ < (PhSe)₂ < (PhTe)₂. The diphenyl diselenide polypyrrole nanocomposite emerged to be better among the studied systems. (PhSe)₂/PPY was characterized and comprehensively evaluated for its photocatalytic activity towards varied dye classes and the colorless isoniazid antibiotic under environmentally viable conditions. Its calculated band potential values and scavenger experiments indicate OH^˙ and O₂^˙− as dominant species in its photocatalytic activity. Control experiments confirmed photocatalytic degradation over photolysis as the dye decolouration mechanism. Taken together, (PhSe)₂/PPY emerges as a good propensity photocatalyst worthy of real time customization for wastewater treatment on a pilot scale.