Ag/GO/TiO2 nanocomposites: the role of the interfacial charge transfer for application in photocatalysis
Ag/GO/TiO2 nanocomposites: the role of the interfacial charge transfer for application in photocatalysis
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DOI：
10.1088/1361-6528/ac2f24
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发表时间：
2022-01-15
期刊：
影响因子：
3.5
通讯作者：
Viana, Marcelo Machado
中科院分区：
文献类型：
--
作者：
de Almeida, Gabriella Correia;Della Santina Mohallem, Nelcy;Viana, Marcelo Machado
纳米TiO 2半导体纳米粒子在光催化方面的应用受到限制，主要是由于光激发电子的快速复合。与其他纳米粒子/纳米结构的组合已被证明是一个有前途的解决方案，用于提高光催化效率。采用微波辅助快速合成法制备了不同晶相的二氧化钛（TiO 2）纳米粒子，并分别用银纳米粒子（Ag）和氧化石墨烯（GO）对其进行了修饰。采用X射线衍射、透射电子显微镜、X射线能谱、红外光谱和气体吸附等手段对样品进行了表征。在碱性条件（pH = 8）下获得结晶的金红石纳米颗粒，而在酸性条件（pH = 1）下，形成单晶的金红石纳米颗粒。不同的先前干燥方法：使用烘箱和冷冻干燥导致所获得的晶相的差异。与Degussa P25光活性相比，在400 ℃下煅烧的锐钛矿TiO 2和锐钛矿-金红石混合物NP显示出高比表面积、结晶度和减少的电子-空穴复合的特性，这有助于增强的光催化活性。评价了银纳米颗粒和GO添加到TiO 2纳米粉末中对纳米活性的影响。亚甲基蓝和罗丹明B染料的光降解的改善，观察到的金红石型和金红石型二氧化钛纳米复合材料。我们注意到，TiO 2纳米颗粒降解53%的罗丹明B，当用GO官能化时，光降解增加到69%。相比之下，添加银纳米粒子的TiO 2的染料降解增加到97%，在180分钟。因此，我们发现，在TiO 2纳米复合材料中，银纳米粒子表现出更好的界面电荷转移比GO，有助于更有效地对染料的光降解过程。
TiO2 semiconductor nanoparticles (NPs) in the anatase phase have presented limitations of application in photocatalysis, mainly due to the fast recombination of photoexcited electrons. The combination with other nanoparticles/nanostructures has been shown to be a promising solution for increasing photocatalytic efficiency. In this work, titanium dioxide (TiO2) nanoparticles in different crystalline phases were prepared through a rapid microwave-assisted synthesis and modified by silver nanoparticles (Ag) and graphene oxide (GO). The samples were characterized by x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, infrared spectroscopy and gas adsorption. Crystalline anatase NPs were obtained in basic conditions (pH = 8) while in acidic conditions (pH = 1), single-crystalline rutile NPs were formed. Different previous drying methods: oven and freeze-drying used led to a differentiation in crystallographic phases obtained. Anatase TiO2 and anatase-rutile mixture NPs calcined at 400 degrees C showed properties as high specific surface area, crystallinity and reduced electron-hole recombination which contributed to an enhanced photocatalytic activity, when compared to the Degussa P25 photoactivity. The effect of silver nanoparticles and GO addition to TiO2 nanopowder was evaluated for photocatalysis activity. An improvement in the methylene blue and rhodamine B dyes photodegradation was observed for both anatase and rutile TiO2 nanocomposites. We noted that anatase TiO2 nanoparticles degraded 53% of rhodamine B, and when functionalized with GO, the photodegradation increased to 69%. Comparatively, the addition of silver nanoparticles to anatase TiO2 increased the dye degradation to 97% in 180 min. Hence, we revel that in the TiO2 nanocomposites, silver nanoparticles showed better interfacial charge transfer than GO, contributing more effectively to the dye photodegradation process.