Aqueous synthesis of Nb-modified SnO ₂ quantum dots for efficient photocatalytic degradation of polyethylene for <i>in situ</i> agricultural waste treatment

Abstract Low density polyethylene is widely used in agricultural production. It is of low cost and able to significantly improve the quality of fruits. However, its decomposition under natural circumstances needs more than one hundred of years. If not removed in time, it is hazardous to the ecological environment and crops. Up to now, the removal techniques of polyethylene films are polluted, expensive, and difficult to employ. A novel method is proposed for in situ removal of polyethylene by an effective and environmental friendly technique with low cost. The Nb-modified SnO 2 quantum dots are prepared for the efficient photocatalytic degradation of polyethylene under visible light. The green synthesis of the photocatalyst includes the procedures of hydrolysis, oxidation, and hydrothermal treatment in aqueous solution. The Nb-modified SnO 2 has a band gap of 2.95 eV, which enhances its absorption of visible light. A degradation efficiency of 29% is obtained within 6 h under visible irradiation. The hydroxyl radicals ( • OH) are main active species in the degradation process. The prepared Nb-SnO 2 quantum dots demonstrate a promising application in the photocatalytic degradation of polyethylene, contributing a novel strategy for the in situ treatment of agricultural wastes.