Gupta Shalu, Kumar Rakesh
Department of Physics and Astrophysics, Central University of Haryana, Mahendergarh, India 123031.
Langmuir. 2025 Jul 1;41(25):16160-16179. doi: 10.1021/acs.langmuir.5c01341. Epub 2025 Jun 16.
This work demonstrates the engineering of an rGO-wrapped g-CN/SnO ternary heterojunction-based photocatalyst via a one-step in situ hydrothermal technique. The well-positioned CB edge of g-CN and the VB of SnO create a type-II heterojunction, making g-CN/SnO a promising photocatalyst for efficient redox reactions. Further, the incorporation of rGO, with its high specific surface area, significantly enhances the density of active site availability of the resulting ternary rGO/g-CN/SnO heterostructure. The reduced band gap and formation of the multiple heterojunctions improve the separation and migration efficiency of photogenerated charge carriers, making the rGO/g-CN/SnO heterojunction highly effective for removing a diverse category of pollutants. A small dose of 0.3 mg/mL of the ternary heterostructure degrades 99.3% of RhB dye under the exposure of simulated solar light for 40 min. Remarkably, the ternary heterostructure exhibits exceptional photodegradation efficiency for a mixture of dyes (MB + RhB + MO) with a high concentration of 30 mg/L, achieving removal rates of 99.99%, 71.4%, and 71%, respectively, within 40 min of irradiation. Moreover, first- and second-order in addition to the intraparticle diffusion models were used to determine the rate constants and equilibrium adsorption capacities of the rGO/g-CN/SnO heterostructure, uncovering the underlying adsorption mechanisms. To comprehend the mechanistic intricacies underlying photocatalysis, a charge transfer process at the multiple interfaces has been thoroughly discussed using the experimentally determined values of work function and band edge positions from ultraviolet photoelectron spectroscopy and Mott-Schottky analysis, respectively. Eventually, the scavenger's study affirms that the photogenerated e-h pairs, superoxide anion, and hydroxyl free radicals all play an active role in the photodegradation process.
这项工作展示了通过一步原位水热技术制备基于rGO包裹的g-CN/SnO三元异质结光催化剂的过程。g-CN的导带边缘和SnO的价带形成了II型异质结，使g-CN/SnO成为用于高效氧化还原反应的有前景的光催化剂。此外，具有高比表面积的rGO的掺入显著提高了所得三元rGO/g-CN/SnO异质结构活性位点的可利用密度。减小的带隙和多个异质结的形成提高了光生电荷载流子的分离和迁移效率，使rGO/g-CN/SnO异质结对于去除多种污染物非常有效。在模拟太阳光照射40分钟的条件下，0.3 mg/mL的小剂量三元异质结构降解了99.3%的罗丹明B染料。值得注意的是，该三元异质结构对于浓度为30 mg/L的混合染料（亚甲基蓝+罗丹明B+甲基橙）表现出优异的光降解效率，在照射40分钟内分别实现了99.99%、71.4%和71%的去除率。此外，除了颗粒内扩散模型外，还使用一级和二级模型来确定rGO/g-CN/SnO异质结构的速率常数和平衡吸附容量，揭示了潜在的吸附机制。为了理解光催化背后的机制复杂性，分别利用紫外光电子能谱和莫特-肖特基分析实验测定的功函数和带边位置值，深入讨论了多个界面处的电荷转移过程。最终，清除剂研究证实光生电子-空穴对、超氧阴离子和羟基自由基在光降解过程中均发挥了积极作用。
