Synthesis of CdS/MgAl layered double hydroxides for hydrogen production from methanol-water decomposition
Synthesis of CdS/MgAl layered double hydroxides for hydrogen production from methanol-water decomposition
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DOI：
10.1016/j.clay.2016.11.013
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发表时间：
2017-02
影响因子：
5.6
通讯作者：
Sonia Mancipe;F. Tzompantzi;R. Gómez
中科院分区：
文献类型：
--
作者：
Sonia Mancipe;F. Tzompantzi;R. Gómez
采用共沉淀法合成了Mg/Al摩尔比为3：1的MgAl层状双氢氧化物和CdS质量分数分别为5、10、15和20%的CdS/MgAl层状双氢氧化物。固体的X射线衍射（XRD）显示具有R-3 m菱面体对称性的六方晶格中的水滑石型材料的特征反射，另外CdS的纤锌矿型六方晶体结构是作为光催化剂的最有效的晶相。氮吸附等温线，得到的比表面积约30平方米/克的所有CdS/MgAl固体被发现是相同的顺序上发现的MgAl LDH。傅里叶变换红外光谱（FTIR）表明，在LDH的层间区域有一个强烈的CO 32-的ν 3振动（反对称伸缩）谱带，在CdS/MgAl样品中该谱带保持不变.扫描电子显微镜研究耦合到一个检测器的能量色散X射线光谱微分析（SEM/EDS）表明，CdS是很好地分散在MgAl的表面上。UV-Vis光谱显示样品的带隙Eg为约2.30 eV，接近于在CdS参比固体中获得的带隙Eg（2.26 eV）。在紫外光照射下，CdS/MgAl光催化剂对甲醇-水分解制氢反应的催化活性为CdS（53 H2μ mol/CdSg）上级20倍以上（1100 H2μ mol/CdSg），CdS/MgAl 5%为最佳光催化剂。
MgAl layered double hydroxide with molar ratio Mg/Al = 3:1, and CdS/MgAl containing 5, 10, 15 and 20 wt% of CdS were synthesized by the co-precipitation method. X-Ray diffraction (XRD) of the solids showed characteristics reflections of hydrotalcite type materials in a hexagonal lattice with R-3m rhombohedra symmetry, additionally a wurtzite type hexagonal crystalline structure of CdS which is the most efficient crystalline phase as photocatalysts. Nitrogen adsorption isotherms were obtained and specific surface areas around 30 m2/g for all the CdS/MgAl solids were found which are of the same order found on the MgAl LDH. Fourier transform infrared spectroscopy (FTIR) spectra showed an intense band characteristic of ν3vibrations (antisymmetric stretching) of CO32–ions located in the interlamellar region of the LDH and it remains constant in the CdS/MgAl samples. Scanning Electron Microscopy study coupled to a detector for energy dispersive X-ray spectroscopy microanalysis (SEM/EDS) showed that the CdS is well dispersed on the surface of the MgAl. UV–Vis spectroscopy showed that the ban-gap Eg of the samples is around 2.30 eV close to that obtained in the CdS reference solid (2.26 eV). The photocatalytic activity under irradiation UV light of the compounds in the hydrogen production from the methanol-water decomposition was evaluated showing that the activity of CdS/MgAl photocatalysts after 7 h under irradiation was up to 20 times superior (1100 H2μmol/CdSg) than the CdS (53 H2μmol/CdSg), being the CdS/MgAl 5% the best photocatalyst.