In this work, the synthesis and catalytic activity of bimetallic Ag–Au nanoparticles (NPs) supported in TiO₂ mesoporous thin films (MTFs) are presented. The composite materials were obtained through a two‐step procedure, performed at room conditions. In the first step, Ag NPs were grown inside the MTFs by photoreduction. Then, a galvanic replacement reaction with Au was carried out, yielding the bimetallic NPs. The composites were characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS) and X‐ray reflectometry (XRR), which show that the alloyed Ag–Au NPs are present inside the mesopores. Moreover, Ag and Au composition relationship can be controlled by adjusting the reaction times of the photoreduction and galvanic replacement reactions, respectively. Pores remain accessible after NPs synthesis, a feature that ensures their possible applications in any device that requires the contact between the NPs and the medium. Catalytic activity of the composites towards 4‐nitrophenol reduction by sodium borohydride was evaluated. Although all the bimetallic systems exhibit improved catalytic properties in comparison with the monometallic Ag composite, the sample with lower Au/Ag relationship is the most effective. For the first time, to the best of our knowledge, bimetallic Au–Ag NPs are encapsulated inside mesoporous TiO₂ films, paving the way towards a wide variety of applications.

中文翻译：

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介孔二氧化钛薄膜内部的双金属Ag-Au纳米颗粒：通过光还原和电取代合成以及催化活性

在这项工作中，TiO ₂负载的双金属Ag-Au纳米颗粒（NPs）的合成和催化活性介绍了介孔薄膜（MTF）。复合材料是通过在室温下进行的两步过程获得的。第一步，Ag NP通过光还原在MTF内部生长。然后，用Au进行电流置换反应，得到双金属NP。通过紫外/可见光谱，透射电子显微镜（TEM），X射线光电子能谱（XPS）和X射线反射仪（XRR）对复合材料进行了表征，表明合金化的Ag-Au NP存在于介孔内部。此外，可以通过分别调节光还原反应和电流置换反应的反应时间来控制Ag和Au的组成关系。NP合成后毛孔仍然可及，该功能可确保将它们应用在需要NP与介质接触的任何设备中。评估了复合材料对氢硼氢化钠还原4-硝基苯酚的催化活性。尽管与双金属Ag复合材料相比，所有双金属体系均显示出改进的催化性能，但具有较低Au / Ag关系的样品最为有效。据我们所知，这是第一次将双金属Au-Ag NP封装在介孔TiO内₂部影片，为广泛的应用铺平了道路。