Abstract A new synthetic smectite-like vanadosilicate, named Vanadosilicate Araraquara Madrid (VAM), containing V3+ was prepared by a hydrothermal method and its behavior as catalyst for methanol oxidation was investigated by X-ray Absorption Spectroscopy (XAS) under operando conditions. The samples were characterized by powder X-ray Diffraction (XRD), Scanning and Transmission Electronic Microscopy (SEM and TEM), CHN chemical analysis, as well as Nuclear Magnetic Resonance spectroscopy, Ultraviolet–visible spectroscopy (UV–Vis) and XAS. The use of VCl3 as a source of vanadium in low oxidation state (V3+) together with a mixture of hexamethyleneimine (HMI) and N,N,N-trimethyl-1-adamantamonium hydroxide (TMAdaOH) and the preparation of the synthesis mixture under inert atmosphere are mandatory for an efficient formation of this smectite-like vanadosilicate. XRD analyses show the synthetic smectite-like vanadosilicate to be impurity free and dioctahedral smectite peaks were observed. TEM observations together with EDS analyses indicate that the chemical composition is consistent with the dioctahedral structure. XAS measurements have revealed that six-coordinated vanadium is present on VAM, in an environmental similar to that reported for roscoelite mineral. The catalytic properties of this material were evaluated during methanol transformation under operando conditions. The reaction mechanism under different atmospheres was investigated and the results indicated that the process under He leads to the formation of H2 and CO, while the presence of oxygen shifts the mechanism toward the partial oxidation of methanol.

中文翻译：

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骨架中含有V3+的新型合成类蒙脱石钒硅酸盐

摘要 采用水热法制备了一种新型合成类蒙脱石钒硅酸盐，名为V3+ V3+，并在操作条件下通过X射线吸收光谱(XAS)研究了其作为甲醇氧化催化剂的行为。通过粉末 X 射线衍射 (XRD)、扫描和透射电子显微镜 (SEM 和 TEM)、CHN 化学分析以及核磁共振光谱、紫外-可见光谱 (UV-Vis) 和 XAS 对样品进行表征。使用 VCl3 作为低氧化态钒 (V3+) 的来源以及六亚甲基亚胺 (HMI) 和 N,N 的混合物，N-三甲基-1-金刚烷氢氧化物 (TMAdaOH) 和在惰性气氛下制备合成混合物是有效形成这种类蒙脱石钒硅酸盐的必要条件。XRD 分析显示合成的类蒙脱石钒硅酸盐不含杂质并且观察到二八面体蒙脱石峰。TEM 观察和 EDS 分析表明化学成分与二八面体结构一致。XAS 测量表明，六配位钒存在于 VAM 中，其环境与所报道的 roscoelite 矿物相似。在操作条件下的甲醇转化过程中评估了该材料的催化性能。