Visible‐light enhanced tetracycline degradation via SnO₂/TiO₂‐Ni@rGO ternary heterostructures

Abstract

This study explores the synthesis, characterization, and photocatalytic performance of a SnO2/TiO2‐Ni@rGO nanocomposite for tetracycline (TC) degradation under visible light irradiation. The nanocomposite was precisely designed to enhance structural stability, charge transfer efficiency, and catalytic activity. X‐ray diffraction (XRD) analysis confirmed the structural integrity of the SnO2/TiO2‐Ni@rGO composite, demonstrating excellent reusability and resistance to photo‐corrosion after multiple cycles. Photocatalytic experiments revealed that the SnO2/TiO2‐Ni@rGO nanocomposite significantly outperformed individual SnO2/TiO2‐Ni and rGO catalysts, achieving a remarkable 94.6% degradation of TC within 60 min. The degradation process followed pseudo‐first‐order kinetics, with a rate constant (k) of 0.046 min−1. The Z‐scheme charge transfer mechanism facilitated efficient separation and migration of photogenerated charge carriers, generating reactive oxygen species such as superoxide (•O2−) and hydroxyl (•OH) radicals crucial for the oxidation of TC. Radical scavenger studies confirmed that superoxide and hydroxyl radicals were the primary active species. The SnO2/TiO2‐Ni@rGO composite also exhibited excellent reusability, maintaining high catalytic performance over four consecutive cycles. These findings suggest that the SnO2/TiO2‐Ni@rGO nanocomposite is a promising candidate for the efficient and sustainable photocatalytic degradation of persistent organic pollutants like TC, offering significant potential for environmental remediation applications.