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Unraveling the Role of Cu0 and Cu+ Sites in Cu/SiO2 Catalysts for Water‐Gas Shift Reaction
ChemCatChem ( IF 3.8 ) Pub Date : 2020-06-19 , DOI: 10.1002/cctc.202000523 Chongqi Chen 1 , Hongju Ren 1 , Yuanyuan He 1 , Yingying Zhan 1 , Chaktong Au 1 , Yu Luo 1 , Xingyi Lin 1 , Shijing Liang 1 , Lilong Jiang 1
ChemCatChem ( IF 3.8 ) Pub Date : 2020-06-19 , DOI: 10.1002/cctc.202000523 Chongqi Chen 1 , Hongju Ren 1 , Yuanyuan He 1 , Yingying Zhan 1 , Chaktong Au 1 , Yu Luo 1 , Xingyi Lin 1 , Shijing Liang 1 , Lilong Jiang 1
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CuOx/SiO2 precursor was successfully fabricated by an ammonia evaporation hydrothermal method. Upon reduction in 5 vol % H2/N2 at 250, 300, 350, 400, or 450 °C, CuO and copper phyllosilicate species in the precursor bring about the formation of highly dispersed Cu0 and Cu+ species, respectively. The Cu+/Cu0 ratios were studied by XAES technique, while the particle sizes were estimated on the basis of HRTEM images. It is disclosed that the ratios and particle sizes varied with CuOx/SiO2 reduction temperatures. The results of in situ DRIFTS and XAES characterization reveal that both Cu0 and Cu+ are active for CO adsorption and water dissociation, especially so with Cu0 and Cu+ particles of small sizes. It was also observed that the adsorption of CO on Cu+ is stronger than that on Cu0, and Cu0 is more active than Cu+ for water dissociation. Among the prepared Cu/SiO2 catalysts, the one resulted from precursor reduction at 300 °C shows the highest CO conversion in WGS reaction, which is attributed to the small size of Cu0 (2.45 nm) and the large amount of Cu+.
中文翻译：
阐明Cu / SiO2催化剂中Cu0和Cu +位在水煤气变换反应中的作用
通过氨蒸发水热法成功制备了CuO x / SiO 2前驱体。在250、300、350、400或450℃下降低5 vol％H 2 / N 2时，前体中的CuO和层状硅酸铜物质分别导致高度分散的Cu 0和Cu +物质的形成。通过XAES技术研究了Cu + / Cu 0的比率，同时根据HRTEM图像估算了粒径。公开了比率和粒度随CuO x / SiO 2还原温度而变化。原位结果DRIFTS和XAES表征表明，Cu 0和Cu +均对CO吸附和水离解具有活性，特别是对于小尺寸的Cu 0和Cu +颗粒而言。还观察到，CO对Cu +的吸附强于对Cu 0的吸附，并且Cu 0对Cu的解离活性比Cu +高。在制备的Cu / SiO 2催化剂中，前驱体在300°C下还原得到的催化剂在WGS反应中显示出最高的CO转化率，这归因于Cu 0的尺寸小（2.45 nm）和大量的Cu +。
更新日期：2020-06-19
中文翻译：
阐明Cu / SiO2催化剂中Cu0和Cu +位在水煤气变换反应中的作用
通过氨蒸发水热法成功制备了CuO x / SiO 2前驱体。在250、300、350、400或450℃下降低5 vol％H 2 / N 2时，前体中的CuO和层状硅酸铜物质分别导致高度分散的Cu 0和Cu +物质的形成。通过XAES技术研究了Cu + / Cu 0的比率，同时根据HRTEM图像估算了粒径。公开了比率和粒度随CuO x / SiO 2还原温度而变化。原位结果DRIFTS和XAES表征表明，Cu 0和Cu +均对CO吸附和水离解具有活性，特别是对于小尺寸的Cu 0和Cu +颗粒而言。还观察到，CO对Cu +的吸附强于对Cu 0的吸附，并且Cu 0对Cu的解离活性比Cu +高。在制备的Cu / SiO 2催化剂中，前驱体在300°C下还原得到的催化剂在WGS反应中显示出最高的CO转化率，这归因于Cu 0的尺寸小（2.45 nm）和大量的Cu +。
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