Ag2O was synthesized by the precipitation method and it was used as support to prepare Ag/Ag2O nanocomposites using different sodium citrate volumes to control the size and amount of Ag nanoparticles. Materials were characterized by X-ray powder diffraction, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning and transmission electron microscopy and nitrogen adsorption–desorption at − 196 °C analyses, respectively. Ibuprofen was selected as a probe molecule and materials were assessed as photocatalysts under simulated visible light irradiation. The SEM and TEM analysis revealed the presence of Ag nanoparticles over Ag2O support showing a size increase as citrate volume increased. By means of DRS analysis a band gap shift was observed, suggesting the formation of metallic silver during Ag impregnation while XPS results proved the co-existence of Ag0 and Ag2O composites. On the other hand, the photocatalysis results revealed the formation of intermediaries during ibuprofen photodegradation. Visible light absorption by Ag nanoparticles produced superoxide anion radicals (due to surface plasmon resonance) that enhanced the formation of intermediaries. The reaction mechanism proposed involves the generation of a Ag/Ag2O heterojunction where the metal acts as an electron scavenger decreasing the recombination of the e−–h+ pair.

中文翻译：

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Ag2O 和 Ag/Ag2O 复合材料在模拟可见光照射下光降解布洛芬

Ag2O 是通过沉淀法合成的，并将其用作载体制备 Ag/Ag2O 纳米复合材料，使用不同的柠檬酸钠体积来控制 Ag 纳米粒子的尺寸和数量。材料分别通过 X 射线粉末衍射、漫反射光谱、X 射线光电子能谱、扫描和透射电子显微镜以及 - 196 °C 下的氮吸附-解吸分析进行表征。布洛芬被选为探针分子，材料在模拟可见光照射下被评估为光催化剂。SEM 和 TEM 分析显示 Ag 纳米粒子在 Ag2O 载体上的存在显示出随着柠檬酸盐体积增加而尺寸增加。通过 DRS 分析观察到带隙偏移，表明在银浸渍过程中形成了金属银，而 XPS 结果证明了 Ag0 和 Ag2O 复合材料的共存。另一方面，光催化结果揭示了在布洛芬光降解过程中中间体的形成。银纳米粒子对可见光的吸收产生了超氧阴离子自由基（由于表面等离子体共振），从而增强了中间体的形成。所提出的反应机制涉及生成 Ag/Ag2O 异质结，其中金属充当电子清除剂，减少 e--h+ 对的复合。银纳米粒子对可见光的吸收产生了超氧阴离子自由基（由于表面等离子体共振），从而增强了中间体的形成。所提出的反应机制涉及生成 Ag/Ag2O 异质结，其中金属充当电子清除剂，减少 e--h+ 对的复合。银纳米粒子对可见光的吸收产生了超氧阴离子自由基（由于表面等离子体共振），从而增强了中间体的形成。所提出的反应机制涉及生成 Ag/Ag2O 异质结，其中金属充当电子清除剂，减少 e--h+ 对的复合。