Manuda K R Jaliya, Tillekaratne Aashani, Jayasundara Dilushan R
Department of Physics, University of Colombo, Colombo 03, Sri Lanka.
Department of Chemistry, University of Colombo, Colombo 03, Sri Lanka.
iScience. 2025 Mar 27;28(5):112304. doi: 10.1016/j.isci.2025.112304. eCollection 2025 May 16.
Titanium dioxide (TiO) has been extensively incorporated with reduced graphene oxide (rGO) to synthesize visible light (Vis) active photocatalysts. Here, we synthesized such rGO-TiO nanocomposite with 10% rGO by mass. The photocatalytic activity of rGO-TiO was quantitatively evaluated using quartz crystal microbalance (QCM). The real-time QCM data resulted in different photocatalytic degradation percentages of methyl orange (MO) at the solid-air interface under ultraviolet (UV) and Vis irradiations. Conventional UV-Vis studies at the solid-liquid interface revealed that a unique hypsochromic effect occurs selectively under Vis irradiation. Radical scavenger studies confirmed that photogenerated holes are the primary active species contributing to this wavelength dependence. The degradation mechanisms under both irradiations are proposed based on the co-catalyzing and photosensitizing dual nature of rGO. The results of this study enhance the empirical knowledge of modified TiO photocatalysts while signifying the impact of irradiation wavelength on the extent and mechanism of photocatalytic degradation.
二氧化钛（TiO）已被广泛地与还原氧化石墨烯（rGO）结合，以合成可见光（Vis）活性光催化剂。在此，我们合成了质量分数为10% rGO的rGO-TiO纳米复合材料。使用石英晶体微天平（QCM）对rGO-TiO的光催化活性进行了定量评估。实时QCM数据得出了在紫外（UV）和可见光照射下，甲基橙（MO）在固-气界面处不同的光催化降解百分比。在固-液界面进行的传统紫外-可见研究表明，在可见光照射下会选择性地出现独特的紫移效应。自由基清除剂研究证实，光生空穴是导致这种波长依赖性的主要活性物种。基于rGO的共催化和光敏双重性质，提出了两种照射条件下的降解机制。这项研究的结果增进了对改性TiO光催化剂的经验认识，同时表明了照射波长对光催化降解程度和机制的影响。
