Harnessing Protein Waste into Reduced Graphitic Carbon Oxide‐Copper‐Collagen Nanocomposite for Visible Light Photocatalytic Degradation of Nano Plastics

Abstract Nano and micro plastics are harmful to the aqueous environment and the current treatment systems are either ineffective or expensive, which restricts their widespread use. In this research, reduced graphitic carbon oxide (rGO)‐Cu nanoparticles crosslinked with collagen support (rGO‐Cu/Coll) are employed as an efficient photocatalyst for the degradation of polystyrene (PS) nano plastics in water. It is shown that rGO‐Cu/Coll nanocomposite can degrade PS nano plastics when subjected to simulated visible light and direct sunlight. In the photocatalytic degradation of PS nano plastics, the reactive radical species (^•OH and O₂^•−) produced on the surfaces of rGO‐Cu/Coll nanocomposite materials play major roles in de‐polymerization. The investigation of the FESEM, Raman, and UV–vis spectra of the irradiated and non‐irradiated samples reveal observable changes, including the distorted morphology and formation of a new band, with longer exposure times and greater degradation. Additionally, evidence for the photodegradation of PS chains is demonstrated by the observed increase in the intensities of the carboxylate, carbonyl, and hydroxyl absorption regions of the ATR‐FTIR spectra. The study provides a simple approach to the battle against plastic pollution in aquatic ecosystems using green photocatalysts under visible light including direct sunlight without consuming additional energy.