Unraveling the Chemistry of PVP in Engineering CdS Nanoflowers for Sunlight-Driven Photocatalysis

Abstract

Photocatalysis, a light-driven process where a nanostructured catalyst accelerates the chemical reactions without being consumed, offers an effective remediation solution. However, synthesizing a stable morphology and efficient visible-light-driven photocatalyst remains a challenging task. In this work, chemistry of synthesizing three dimensional (3D) cadmium sulfide nanoflowers (CdS NFs) photocatalyst with excellent optoelectronic properties and promising natural solar driven photocatalytic activity has been reported. CdS NFs exhibit superior light absorption due to their unique 3D structure enhancing their photocatalytic performance. This study investigates the hydrothermal formulation of CdS NFs using polyvinylpyrrolidone (PVP) as a capping agent with emphasis on its role in optimizing 3D NFs morphology as well as their optoelectronic properties. Various microscopy and spectroscopic studies of synthesized PVP assisted CdS nanostructures confirm the formation of 3D NFs with enhanced visible light absorption capability having band gap varied from 2.24 to 2.15 eV and lower electron-hole recombination rate. The solar driven photocatalytic activity show that the optimized PVP assisted CdS NFs significantly improves the methylene blue photodegradation achieving 93% degradation in 180 minutes. Furthermore, the photocatalytic performance of CdS NFs was also evaluated against anionic and cationic dyes as well as pharmaceutical drug pollutants, showing broad degradation capability. In addition, electrochemical impedance spectroscopy (EIS) and BET surface area analyses confirm the improved charge transfer dynamics and high surface area favorable for photocatalysis. Furthermore, mechanism and chemistry of role of PVP in establishing 3D CdS NFs morphology with better photocatalytic performance along with photostability as well as recyclability have been discussed. This study highlights the impact of capping agents in optimizing CdS NFs morphology and optical properties for environmental remediation and energy applications.