Catalytic Behaviour of CuO-CeO2 Systems Prepared by Different Synthetic Methodologies in the CO-PROX Reaction under CO2-H2O Feed Stream
Catalytic Behaviour of CuO-CeO2 Systems Prepared by Different Synthetic Methodologies in the CO-PROX Reaction under CO2-H2O Feed Stream
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DOI：
10.3390/catal7050160
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发表时间：
2017-05
期刊：
影响因子：
3.9
通讯作者：
J. A. Cecilia;A. Arango-Díaz;J. Marrero-Jerez;P. Núñez;E. Moretti;L. Storaro;E. Rodriguez-castellon
中科院分区：
文献类型：
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作者：
J. A. Cecilia;A. Arango-Díaz;J. Marrero-Jerez;P. Núñez;E. Moretti;L. Storaro;E. Rodriguez-castellon
采用不同的制备方法（硝酸盐前驱体煅烧法、尿素-硝酸盐热燃烧法、冷冻干燥法、聚甲基丙烯酸甲酯PMMA微球为模板法、NaOH或尿素分解为沉淀剂沉淀法）合成了Cu含量为6 wt%的CuO-CeO2催化剂。通过X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、拉曼光谱、-196℃N2吸附-脱附、H2热程序还原（H2-TPR）和X射线光电子能谱（XPS）对所得材料进行了表征。该催化剂表现出氧化铜的高分散性，在过量氢气的 CO 优先氧化 (CO-PROX) 中，在 115 °C 下获得了 90-100% 的 CO 转化率，并且即使在运行 48 小时后仍保持这种活性。进料流中加入 CO2 和 H2O（模拟 PROX 装置）导致 CO 转化率下降，但使用 PMMA 微球作为模板合成的催化剂在 115 °C 下保持 95% 的 CO 转化率。该催化剂在实际操作条件下也表现出优异的催化性能，这要归功于许多伴随因素，例如非常小的CeO2粒径（5.6 nm）、表面富含易还原的铜（原子比Cu/Ce = 0.35）以及材料的独特形貌和孔隙率。
CuO-CeO2 catalysts, with 6 wt % of Cu, have been synthesised by different preparation methods (calcination of nitrate precursors, thermal urea-nitrate combustion, freeze-drying method, using polymethyl metacrylate PMMA microspheres as template and precipitation using NaOH or the decomposition of urea as precipitating agents). The obtained materials have been characterised by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, N2 adsorption-desorption at −196 °C, H2 thermoprogrammed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The catalysts displayed high dispersion of copper oxide, obtaining CO conversion values of 90–100% at 115 °C in the CO preferential oxidation in excess of hydrogen (CO-PROX) and maintaining this activity even after 48 h of time on stream. The incorporation of CO2 and H2O in the feed stream (simulating a PROX unit) caused a decrease in the CO conversion, except for the catalyst synthesised using PMMA microspheres as a template which maintained a CO conversion of 95% at 115 °C. This catalyst exhibits an excellent catalytic performance, also under real operating conditions, thanks to many and concomitant factors, such as the very small CeO2 particle size (5.6 nm), the surface being rich in copper (atomic ratio Cu/Ce = 0.35) that is easily reducible, and the peculiar morphology and porosity of the material.