富氢气氛下CeO_2-NiO纳米棒催化剂的CO选择性氧化性能研究

采用水热法制备了一系列不同Ce/Ni物质的量比的纳米棒CeO_2(x)-NiO催化剂。运用低温N_2吸附-脱附、XRD、TEM、拉曼光谱、H_2-TPR及XPS等技术对催化剂的形貌、结构进行了表征。考察了Ce/Ni物质的量比对CeO_2(x)-NiO催化剂形貌及富氢气氛下CO选择性氧化(CO PROX)反应性能的影响。TEM测试结果表明,调变Ce/Ni物质的量比可制得不同粒径的CeO_2(x)-NiO纳米棒催化剂。H_2-TPR测试结果表明,将NiO掺入CeO_2可提升Ce O_2(x)-NiO催化剂的氧化还原能力。拉曼光谱及XPS测试结果表明,镍含量较低时,CeO_2(x)-NiO催化剂表面活性氧物种及氧空位含量均较多,利于提升其催化性能。CO PROX催化性能测试结果显示,镍含量较低的CeO_2(0.89)-NiO纳米棒催化剂的活性和选择性最好,在170-220℃的反应条件下,CO转化率为100%,CO_2选择性为52%。

Performance of CO preferential oxidation of CeO2-NiO nanorod catalyst in H2-rich stream

A series of nanorod CeO₂(x)-NiO composite oxides catalysts with different Ce/Ni molar ratios have been synthesized by hydrothermal method. Their morphology and structure were characterized by N₂ sorption-desorption, XRD, TEM, Raman spectra, H₂-TPR and XPS. The effects of Ce/Ni molar ratio on the morphology and catalytic activity of CeO₂(x)-NiO composite oxides catalysts for CO preferential oxidation (CO PROX) in hydrogen-rich stream were studied. TEM results indicate that nanorod CeO₂(x)-NiO composite oxides catalysts with different sizes can be obtained by adjusting Ce/Ni molar ratio. H₂-TPR results show that introduction of NiO into CeO₂ enhance the redox ability of CeO₂(x)-NiO composite oxides catalysts. Raman spectra and XPS results indicate that CeO₂(x)-NiO composite oxides catalysts with low nickel content have much more active oxygen species and oxygen vacancies, which are beneficial to improve its catalytic performance. CeO₂(0.89)-NiO nanorod catalysts with low nickel content exhibits the highest activity and CO₂ selectivity, the CO conversion is 100% and the CO₂ selectivity is about 52% in the reaction temperature range of 170-220 ℃ for CO PROX in hydrogen-rich stream.