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首页> 外文期刊>RSC Advances >Mesoporous cerium–zirconium oxides modified with gold and copper – synthesis, characterization and performance in selective oxidation of glycerol
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Mesoporous cerium–zirconium oxides modified with gold and copper – synthesis, characterization and performance in selective oxidation of glycerol

机译：金和铜改性的介孔铈锆氧化物-甘油的选择性氧化和合成，表征及性能

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The main goal of this work was the synthesis of mesoporous ceria, zirconia and cerium–zirconium oxides, the application of these supports for the preparation of monometallic (copper or gold) and bimetallic (copper and gold) catalysts and characterisation of their performance in the oxidation of glycerol in basic aqueous solution in the presence of oxygen. The methods applied for the study included: adsorption/desorption of nitrogen, XRD, ICP-OES, XPS, UV-vis, STEM-EDXS, H2-TPR. The presence of the following species Au0, Auδ+, negatively charged gold Au? or Au0 in bimetallic particles, Cu+, Cu2+, Ce3+ and Ce4+, Zr4+ was confirmed and their content was found to depend on the catalyst composition. The interaction between gold and copper species in bimetallic samples caused the formation of the negative charge on gold and the increase of the amount of Cu+ cations on the catalyst surface. This feature and the higher gold dispersion gave rise to a significant increase in the catalytic activity in glycerol oxidation of bimetallic catalysts with respect to that of monometallic samples. The high selectivity to glyceric acid (GLA) is an important advantage of the bimetallic catalysts (copper–gold), especially those loaded on mixed cerium–zirconium oxides. The bimetallic catalysts were stable and in the second run of the reaction they almost did not change glycerol conversion and increased the selectivity to GLA. The texture parameters of the catalysts had also impact on the selectivity of the reaction: the lower the microporosity the higher the selectivity to GLA. The role of the support is the interaction with copper and gold active species and enhancement of the reagents' chemisorption and electron transfers.
机译：这项工作的主要目的是合成介孔二氧化铈，氧化锆和铈锆锆氧化物，将这些载体用于制备单金属（铜或金）和双金属（铜和金）催化剂，并表征它们的性能。氧气存在下碱性水溶液中甘油的氧化。研究方法包括：氮的吸附/解吸，XRD，ICP-OES，XPS，UV-vis，STEM-EDXS，H 2 -TPR。下列带负电的物种Au 0 ，Au δ + 的存在双金属粒子Cu + 中的金Au ？ 或Au 0 ，Cu 2 + ，Ce 3 + 和Ce 4+确认了 ，Zr 4 + ，发现它们的含量取决于催化剂的组成。双金属样品中金和铜物质之间的相互作用导致金上形成负电荷，并导致催化剂表面Cu + 阳离子的数量增加。该特征和较高的金分散性使双金属催化剂的甘油氧化催化活性相对于单金属样品显着提高。对甘油酸（GLA）的高选择性是双金属催化剂（铜金）的重要优势，尤其是负载在铈锆锆氧化物混合液上的那些催化剂。双金属催化剂是稳定的，并且在反应的第二轮中，它们几乎不改变甘油的转化并增加了对GLA的选择性。催化剂的织构参数也影响反应的选择性：微孔率越低，对GLA的选择性越高。载体的作用是与铜和金活性物质相互作用，并增强试剂的化学吸附和电子转移。

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