Abstract In this work, Ag2Mo1-xWxO4 (x = 0, 0.25, 0.50, 0.75 and 1 mol%) heterostructures were synthesized by a microwave-assisted hydrothermal (MAH) method under 140 °C. The powders are characterized by X-ray diffractogram (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and spectroscopy in the ultraviolet–visible region (UV–Vis). The photocatalytic degradations are investigated by methylene blue (cationic) and methyl orange (anionic) dyes and the mechanisms acting in the photocatalysis are estimated by a scavenger’s methodology. The diffractograms indicate that the MAH method provides powders with high crystallinity and without secondary phases. SEM micrographs indicate that the Ag2MoO4 phase is formed by micrometric particles with a coarse aspect and the Ag2WO4 phase is formed by micrometric rods with a square cross-section. The direct Egap varied from 3.46 to 3.23 eV for the Ag2MoO4 and Ag2WO4 phases, respectively. The adsorptive and photocatalytic tests showed that the Ag2WO4 phase has a better performance against both dyes than the Ag2MoO4 phase, being the best performance against the MB dye (complete discoloration after 20 min). The scavenger’s tests showed that the positive charges (h+) are the main mechanism acting in the photocatalysis for the Ag2MoO4 phase, while the h+ and hydroxyl radicals (∙OH) have a similar influence in the Ag2WO4 phase. Photocatalytic tests of reuse indicated that the samples have a good photocatalytic capacity even in the third consecutive cycle.

中文翻译：

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微波辅助水热合成 Ag2Mo1-xWxO4（x = 0、0.25、0.50、0.75 和 1 mol%）异质结构，用于增强有机染料的光催化降解

摘要 在这项工作中，Ag2Mo1-xWxO4 (x = 0, 0.25, 0.50, 0.75 和 1 mol%) 异质结构是通过微波辅助水热 (MAH) 方法在 140 °C 下合成的。通过 X 射线衍射图 (XRD)、拉曼光谱、扫描电子显微镜 (SEM)、能量色散 X 射线光谱和紫外-可见光区 (UV-Vis) 光谱对粉末进行表征。通过亚甲蓝（阳离子）和甲基橙（阴离子）染料研究光催化降解，并通过清除剂方法评估光催化作用的机制。衍射图表明，MAH 方法提供了具有高结晶度且没有第二相的粉末。SEM 显微照片表明 Ag2MoO4 相由粗大的测微颗粒形成，Ag2WO4 相由方形横截面的测微棒形成。Ag2MoO4 和 Ag2WO4 相的直接 Egap 分别从 3.46 到 3.23 eV。吸附和光催化测试表明，Ag2WO4 相对两种染料的性能都比 Ag2MoO4 相更好，对 MB 染料的性能最好（20 分钟后完全变色）。清除剂的测试表明，正电荷 (h+) 是 Ag2MoO4 相光催化作用的主要机制，而 h+ 和羟基自由基 (∙OH) 在 Ag2WO4 相中具有相似的影响。重复使用的光催化测试表明，即使在连续第三个循环中，样品也具有良好的光催化能力。