富氢气氛下CeO2-NiO纳米棒催化剂的CO选择性氧化性能研究

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

采用水热法制备了一系列不同Ce/Ni物质的量比的纳米棒CeO2(x)-NiO催化剂。运用低温N2吸附-脱附、XRD、TEM、拉曼光谱、H2-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CeO2(x)-NiO催化剂形貌及富氢气氛下CO选择性氧化(COPROX)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CeO2(x)-NiO纳米棒催化剂。H2-TPR测试结果表明,将NiO掺入CeO2可提升CeO2(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,CeO2(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。COPROX催化性能测试结果显示,镍含量较低的CeO2(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%,CO2选择性为52%。

A series of nanorod CeO 2( x )-NiO composite oxides catalysts with different Ce/Ni molar ratios have been synthesized by hydrothermal method. Their morphology and structure were characterized by N 2 sorption-desorption, XRD, TEM, Raman spectra, H 2-TPR and XPS. The effects of Ce/Ni molar ratio on the morphology and catalytic activity of CeO 2( x )-NiO composite oxides catalysts for CO preferential oxidation (CO PROX) in hydrogen-rich stream were studied. TEM results indicate that nanorod CeO 2( x )-NiO composite oxides catalysts with different sizes can be obtained by adjusting Ce/Ni molar ratio. H 2-TPR results show that introduction of NiO into CeO 2 enhance the redox ability of CeO 2( x )-NiO composite oxides catalysts. Raman spectra and XPS results indicate that CeO 2( 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. CeO 2(0.89)-NiO nanorod catalysts with low nickel content exhibits the highest activity and CO 2 selectivity, the CO conversion is 100% and the CO 2 selectivity is about 52% in the reaction temperature range of 170-220 ℃ for CO PROX in hydrogen-rich stream.