Solvothermal synthesized mesoporous BiOCl nano-ellipsoids with oxygen vacancies for photocatalytic degradation of low density polyethylene (LDPE) plastic

Abstract

This study explores mesoporous BiOCl nanoparticles as a promising photocatalyst for low-density polyethylene (LDPE) degradation under visible light for the first time. A solvothermal synthesis yields BiOCl nanoparticles with a high ratio of exposed {010} facets and abundant oxygen vacancies (OVs). These properties, along with the co-existence of Bi³^-x and Bi³⁺^x defect states, promote a tailored surface chemistry with high surface-bound hydroxyl groups. These properties optimize light absorption by inducing favorable surface states, leading to a red shift in the light absorption edge for efficient utilization of visible light. Additionally, OVs suppress the recombination of photo-generated charge carriers and enhance their transfer rate. Furthermore, the free-standing LDPE/BiOCl nanocomposite films of 50μm, prepared via solution casting technique with varying BiOCl weight percentages (3, 5, and 7 wt.%), exhibit remarkable photocatalytic activity. The analysis of photodegraded LDPE confirms the presence of carbonyl groups (C.I.= 86%), cracks, pores, and hydroxyl radicals (•OH), alongside reduced thermal stability and band gap changes. Through meticulous analysis of the results obtained, we have ascertained that the optimal photocatalytic degradation of LDPE is achieved by incorporating up to 5 wt.% of BiOCl.