Hasija Vasudha, Singh Pardeep, Thakur Sourbh, Nguyen Van-Huy, Van Le Quyet, Ahamad Tansir, Alshehri Saad M, Raizada Pankaj, Matsagar Babasaheb M, Wu Kevin C-W
School of Advanced Chemical Sciences, Shoolini University, Solan, Himachal Pradesh, 173212, India.
Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Silesian University of Technology, B. Krzywoustego 4, 44-100, Gliwice, Poland.
Chemosphere. 2023 Apr;320:138015. doi: 10.1016/j.chemosphere.2023.138015. Epub 2023 Feb 4.
Doping-induced vacancy engineering of graphitic carbon nitride (GCN) is beneficial for bandgap modulation, efficient electronic excitation, and facilitated charge carrier migration. In this study, synthesis of oxygen and sulphur co-doped induced N vacancies (OSGCN) by the hydrothermal method was performed to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) antibiotic degradation and H production. The results from experimental and DFT simulation studies validate the synergistic effects of co-dopants and N-vacancies, i.e., bandgap lowering, electron-hole pairs separation, and high solar energy utilization. The substitution of sp N atom by O and S co-dopants causes strong delocalization of HOMO-LUMO distribution, enhancing carrier mobility, increasing reactive sites, and facilitating charge-carrier separation. Remarkably, OSGCN/PMS photocatalytic system achieved 99.4% SMX degradation efficiency and a high H generation rate of 548.23 μ mol g h within 60 min and 36 h, respectively under visible light irradiations. The SMX degradation kinetics was pseudo-first-order with retained recycling efficiency up to 4 catalytic cycles. The results of EPR and chemical scavenging experiments revealed the redox action of reactive oxidative species, wherein O was the dominant reactive species in SMX degradation. The identification of formed intermediates and the SMX stepwise degradation pathway was investigated via LC-MS analysis and DFT studies, respectively. The results from this work anticipated deepening the understanding of PMS activation by substitutional co-doping favoring N-vacancy formation in GCN lattice for improved photocatalytic activity.
掺杂诱导的石墨相氮化碳（GCN）空位工程有利于带隙调制、高效电子激发和促进电荷载流子迁移。在本研究中，采用水热法合成了氧和硫共掺杂诱导的N空位（OSGCN），以活化过一硫酸盐（PMS）用于磺胺甲恶唑（SMX）抗生素降解和产氢。实验和DFT模拟研究结果验证了共掺杂剂和N空位的协同效应，即带隙降低、电子-空穴对分离和高太阳能利用率。O和S共掺杂剂取代sp N原子导致HOMO-LUMO分布强烈离域，增强了载流子迁移率，增加了反应位点，并促进了电荷载流子分离。值得注意的是，在可见光照射下，OSGCN/PMS光催化体系在60分钟和36小时内分别实现了99.4%的SMX降解效率和548.23 μmol g⁻¹ h⁻¹的高产氢率。SMX降解动力学为拟一级反应，循环效率保持高达4个催化循环。EPR和化学清除实验结果揭示了活性氧化物种的氧化还原作用，其中O⁻²是SMX降解中的主要活性物种。分别通过LC-MS分析和DFT研究确定了形成的中间体和SMX的逐步降解途径。这项工作的结果有望加深对通过取代共掺杂促进GCN晶格中N空位形成以提高光催化活性来活化PMS的理解。
