Synthesis of Diverse Ag2O Crystals and Their Facet-Dependent Photocatalytic Activity Examination
Synthesis of Diverse Ag2O Crystals and Their Facet-Dependent Photocatalytic Activity Examination
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DOI：
10.1021/acsami.6b04686
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发表时间：
2016-08-03
影响因子：
9.5
通讯作者：
Huang, Michael H.
中科院分区：
文献类型：
--
作者：
Chen, Ying-Jui;Chiang, Yun-Wei;Huang, Michael H.
采用简单的NH4NO3、NaOH和AgNO3溶液的摩尔比，在较短的反应时间内，在室温下合成了亚微米级的Ag2O立方体、大菱形二面体、三面体、角截断八面体、八面体和菱形十二面体。此外，调节溶液中NH3的浓度可以提供更多的颗粒形态，包括边角截断的立方体、小菱形六面体和边角截断的八面体，以丰富Ag2O的形状多样性。x射线光电子能谱（XPS）表明各种晶体的表面组成为纯Ag2O。用漫反射光谱测定了Ag2O立方体的带隙。采用具有相同颗粒总表面积的Ag2O立方体、八面体和菱形十二面体对甲基橙的降解进行了面相关的光催化活性比较。立方体对该反应具有较高的活性，而八面体和菱形十二面体分别具有中等和低的催化活性。电子顺磁共振（EPR）测量证实了这种反应顺序。虽然所有的Ag2O样品在光催化过程中都表现出明显的蚀刻，但没有产生金属银。
Sub-to micrometer-sized Ag2O cubes, great rhombicuboctahedra, cuboctahedra, corner-truncated octahedra, octahedra, and rhombic dodecahedra have been synthesized at room temperature using simple molar ratios of NH4NO3, NaOH, and AgNO3 solutions with a short reaction time. In addition, tuning the concentration of NH3 in the solution can provide more particle morphologies including edge-and corner-truncated cubes, small rhombicuboctahedra, and edge-truncated octahedra to enrich Ag2O shape diversity. X-ray photoelectron spectroscopy (XPS) spectra indicate surface composition of various crystals as pure Ag2O. Diffuse reflectance spectra have been used to determine the band gap of Ag2O cubes. Ag2O cubes, octahedra, and rhombic dodecahedra having the same total particle surface area were used for facet-dependent photocatalytic activity comparison in the degradation of methyl orange. Cubes are comparably highly active for this reaction, while octahedra and rhombic dodecahedra give moderate and low catalytic activities, respectively. Electron paramagnetic resonance (EPR) measurements confirm this reactivity order. Although all Ag2O samples show significant etching during photocatalysis, metallic silver is not produced.