Delafrouz S, Hasheminiasari M, Alamolhoda S, Masoudpanah S M
School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran.
Heliyon. 2024 Nov 16;10(22):e40464. doi: 10.1016/j.heliyon.2024.e40464. eCollection 2024 Nov 30.
In this study, the main objective was to improve the photocatalytic performance of TiO₂ and g-C₃N₄ under visible light irradiation by the creation of g-CN/TiO heterojunction, where the solution combustion method was utilized to synthesize nanocomposites. The g-CN/TiO nanocomposites were fabricated with a 9:1 wt ratio of g-C₃N₄ to TiO₂ for investigation of the effects of different fuels, including urea, glycine, citric acid, and their mixtures, on the photocatalytic performance of the g-C₃N₄/TiO₂ nanocomposites. The nanocomposites were characterized using various techniques such as diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, (BET) surface area analysis, field emission scanning electron microscopy (FESEM), Raman spectroscopy, and X-ray diffraction (XRD). The nanocomposite synthesized using a mixture of citric acid and urea (TCN-CA/U) depicted 97 % degradation of MB within 2 h of visible light exposure, demonstrating significantly enhanced photocatalytic efficiency. The degradation constant rate of TCN-CA/U (0.02971 min⁻) was approximately 3 times higher than that of pure g-C₃N₄ (0.00952 min⁻) and 13.5 times higher than that of TiO₂ (0.00218 min⁻). Furthermore, the TCN-CA/U nanocomposite showed high degradation efficiencies for Rhodamine B (RhB) (91 %) and Methyl Orange (MO) (61 %) under the same conditions. The observed improvement in photocatalytic performance attributed to several factors, including a fourfold increase in specific surface area (52.5 m/g) compared to g-C₃N₄ (12.2 m/g), a significant reduction in electron-hole pair recombination, and a narrowed band gap energy of 2.57 eV, which played a crucial role in enhancing visible light absorption.
在本研究中，主要目标是通过创建g-CN/TiO异质结来提高TiO₂和g-C₃N₄在可见光照射下的光催化性能，其中采用溶液燃烧法合成纳米复合材料。以g-C₃N₄与TiO₂的重量比为9:1制备g-CN/TiO纳米复合材料，以研究包括尿素、甘氨酸、柠檬酸及其混合物在内的不同燃料对g-C₃N₄/TiO₂纳米复合材料光催化性能的影响。使用各种技术对纳米复合材料进行表征，如漫反射光谱（DRS）、光致发光（PL）光谱、（BET）表面积分析、场发射扫描电子显微镜（FESEM）、拉曼光谱和X射线衍射（XRD）。使用柠檬酸和尿素混合物（TCN-CA/U）合成的纳米复合材料在可见光照射2小时内对亚甲基蓝（MB）的降解率达到97%，表明光催化效率显著提高。TCN-CA/U的降解速率常数（0.02971 min⁻¹）约为纯g-C₃N₄（其降解速率常数为0.00952 min⁻¹）的3倍，是TiO₂（其降解速率常数为0.00218 min⁻¹）的13.5倍。此外，在相同条件下，TCN-CA/U纳米复合材料对罗丹明B（RhB）（91%）和甲基橙（MO）（61%）显示出高降解效率。观察到的光催化性能改善归因于几个因素，包括比表面积（52.5 m²/g）相比g-C₃N₄（12.2 m²/g）增加了四倍、电子-空穴对复合显著减少以及带隙能量变窄至2.57 eV，这在增强可见光吸收方面起到了关键作用。
