The pollution of the water environment by industrial effluents is an ongoing challenge due to the rate of industrialisation and globalisation.

Fabrication of a photocatalyst with the desired characteristics of high charge isolation and expeditious photocatalytic performance is crucial in photocatalysis. Constructing an interfacial chemically bonded S‐scheme heterojunction is an effective path to the realization of high interfacial charge transfer and performance. Herein, Mg‐Bi₂O₃/dark gray g‐C₃N₄ (MBOdCN) S‐scheme heterojunction with Bi‐N bond bridges is successfully constructed using an in situ calcination strategy for oxytetracycline (OTC) degradation. The MBOdCN (1:5) displays outstanding performance with efficiency and rate constant of 99.56% and 0.0235 min⁻¹, respectively. The synergy of n‐π* transition, Mg defects, and Bi–N bond bridges in the MBOdCN enhances the performance of the S‐scheme heterojunction. X‐ray photoelectron spectroscopy (XPS) analysis, work function measurements, and density functional theory (DFT) reveal the formation of MBOdCN S‐scheme heterojunction. In this system, trapping experiments and electron‐spin resonance (ESR) spectroscopy confirm the predominance of ^•O₂⁻ > h⁺ > ^•OH during OTC degradation. The degradation pathways and byproducts are investigated with LC‐MS and the toxicity study is undertaken on the OTC degradation byproducts and photocatalytic materials. This work provides a holistic understanding of the novel S‐scheme heterojunction by introducing interfacial chemical bond bridges and defects as dual charge transfer channels.

The release of common medications and illegal drugs into the environment could be potentially harmful to the ecosystem and hamper the behavior and growth of plants and animals. These pollutants gain access to water through sewage and factory discharges and have been found to exceed safety limits in water bodies. Therefore, there is an urgent need for improved wastewater purification systems. In this study, semiconductor-based heterojunction photocatalyst CuInS₂/CeO₂, synthesized through a facile solvothermal process, was explored for the photocatalytic degradation of ciprofloxacin, commonly used antibiotics. Studies on the electronic properties of the heterojunction revealed interfacial characteristics that were suitable for enhanced charge carrier separation and transport and a potential S-scheme charge transfer mechanism. The heterojunction achieved ∼90% efficiency for the degradation of CIP compared to 60% and 12% reported for CeO₂ and CuInS₂, respectively. This shows an improvement in the activity, which results from the improved charge carrier properties of the heterojunction. Further investigation of the charge transfer mechanism through radical scavenging experiments identified ^•OH, O2^•-, and h⁺ as active species contributing to the catalyst's efficacy. Based on X-ray photoelectron spectroscopy analysis, a proposed S-scheme charge transfer mechanism was suggested for the CuInS₂/CeO₂ heterojunction. The findings indicate the potential of the CuInS₂/CeO₂ heterojunction as a promising photocatalyst for treating waste effluents from the pharmaceutical industry.

DNA interaction withcisandtrans-copper NO complexes favours thecisconfiguration due to low energies observed in thecisconfiguration.