Nejadramezan Mohaddeseh, Ajami Arsalan, Sheibani Saeed
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran.
School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran.
Environ Res. 2025 Jun 24;284:122176. doi: 10.1016/j.envres.2025.122176.
In this study, the carbon nanotubes (CNTs) modified g-CN/ZnO photocatalytic nanocomposite was synthesized through in-situ growth of ZnO nanoparticles on the CNT-loaded graphitic carbon nitride (g-CN) to evaluate its hydrogen production and dye degradation capabilities. The disc-like ZnO nanoparticles were spotted alongside the CNTs on the g-CN surface with a specific surface area of 140.8 m/g. The electrostatic interactions between conjugated bonds of g-CN and π bonds of CNTs resulted in a well-bonded interface and high adsorption of CNTs. CNTs significantly increased the visible light absorption and reduced the band gap energy to 2.45 eV in CNT/g-CN/ZnO (CN/Zn/CNT) nanocomposite. Because of the S-scheme charge transfer mechanism between g-CN (CN) and ZnO and the attendance of CNT as an electron transfer accelerator, CN/Zn/CNT demonstrated the best charge carrier separation and electron transfer to the surface among the samples according to photoluminescence (PL), photocurrent and electrochemical impedance spectroscopy (EIS) examinations. Mott-Schottky analysis and scavenger experiments confirmed the formation of the S-scheme mechanism with hydroxyl and superoxide radicals as the main reactive oxygen species. Due to the high conductivity and well-bonded interface, CNT significantly transferred and recombined ineffective charge carriers within the S-scheme mechanism by creating efficacious charge transfer channels. CN/Zn/CNT nanocomposite photodegraded 93 % of methylene blue (MB). Meanwhile, due to the similar surface charge potential of CN/Zn/CNT with methyl orange (MO) and phenol, only 25 and 52 % of these pollutants were degraded by the nanocomposite, respectively. The efficient charge transfer of the S-scheme mechanism in the water splitting process increased the thermodynamic tendency of the reaction, and the presence of carbon nanotubes as the electron transfer accelerators kinetically impressed the reaction. Hence, the hydrogen production rate in the CN/Zn/CNT nanocomposite reached 690 μmol/g.h, whereas it was 429 and 291 μmol/g.h for gCN/Zn and CN, respectively.
在本研究中，通过在负载碳纳米管（CNT）的石墨相氮化碳（g-CN）上原位生长ZnO纳米颗粒，合成了碳纳米管（CNT）修饰的g-CN/ZnO光催化纳米复合材料，以评估其产氢和染料降解能力。盘状ZnO纳米颗粒与CNT一起分布在g-CN表面，比表面积为140.8 m/g。g-CN的共轭键与CNT的π键之间的静电相互作用导致形成了良好结合的界面以及CNT的高吸附。CNT显著提高了可见光吸收，并将CNT/g-CN/ZnO（CN/Zn/CNT）纳米复合材料的带隙能量降低至2.45 eV。由于g-CN（CN）与ZnO之间的S型电荷转移机制以及CNT作为电子转移促进剂的存在，根据光致发光（PL）、光电流和电化学阻抗谱（EIS）测试，CN/Zn/CNT在样品中表现出最佳的电荷载流子分离和向表面的电子转移。莫特-肖特基分析和清除剂实验证实了以羟基和超氧自由基作为主要活性氧物种的S型机制的形成。由于高导电性和良好结合的界面，CNT通过创建有效的电荷转移通道，在S型机制内显著转移和复合了无效电荷载流子。CN/Zn/CNT纳米复合材料光降解了93%的亚甲基蓝（MB）。同时，由于CN/Zn/CNT与甲基橙（MO）和苯酚具有相似的表面电荷电位，该纳米复合材料分别仅降解了25%和52%的这些污染物。S型机制在水分解过程中的有效电荷转移增加了反应的热力学趋势，并且碳纳米管作为电子转移促进剂的存在从动力学上推动了反应。因此，CN/Zn/CNT纳米复合材料的产氢速率达到690 μmol/g·h，而gCN/Zn和CN的产氢速率分别为429和291 μmol/g·h。
