摘要
通过水热晶化法合成了粒径可控的纳米级球状CeO_2,以不同粒径的CeO_2作为载体采用等体积浸渍法制备了一系列Pt-Ni/CeO_2双金属催化剂,并考察了其在乙醇水蒸气重整制氢(ESR)反应中的应用。采用XRD,SEM,N2吸附脱附和H_2-TPR表征手段对催化剂的理化性质、还原性能等进行了分析,并深入研究催化剂的催化性能。结果表明,以2Pt-6Ni/CeO_2(50nm)为催化剂,在反应温度为450℃、水醇摩尔比为6∶1的条件下反应10h后,乙醇转化率无明显变化,氢气选择性仍保持70%左右,副产物CO选择性仅为1.5%,还有微量的乙醛分子存在。这可归因于活性组分Pt和Ni间的高效协同作用:Pt可促进乙醇分解、脱氢;Ni组分除了较强的C—C键断裂能力外,对水煤气变换反应和甲烷重整也具有一定活性,可以降低产物中CO和CH_4的含量;同时,Pt的存在提高了Ni组分的分散度。此外,具有高氧活性的CeO_2也促进了乙醇水蒸气的解离,克服了金属表面积碳,与Pt,Ni间的交互作用一定程度上提升了催化剂的催化性能。
In this paper,a series of Pt-Ni/CeO 2 bimetallic catalysts were prepared by incipient-wetness impregnation with different sizes of the nanospherical cerium oxide that was prepared by hydrothermal crystallization as carrier,and their application in the reaction of ESR(ethanol steam reforming)was investigated.The physical and chemical properties and the reduction properties of the catalysts were analyzed by XRD,SEM,N 2 adsorption-desorption and H 2-TPR.The in-depth study of the catalytic performance of the catalysts were cauducted.The results show that with 2Pt-6Ni/CeO 2(50 nm)as the catalyst,after 10 h of reaction under reaction temperature of 450℃and the molar ratio of water to alcohol 6∶1,the conversion of ethanol did not change obviously,the selectivity of hydrogen remained about 70%,the selectivity of byproduct CO was 1.5%,and the presence of trace amounts of acetaldehyde molecules was observed.This can be attributed to the synergistic effect between the Pt and Ni active components.Pt can promote the decomposition and dehydrogenation of ethanol.In addition to its strong C-C bond breaking ability,Ni component also has a definite activity on water gas shift reaction and methane reforming,thus reducing the content of CO and CH 4 in the product.Meanwhile,the presence of Pt improves the dispersion of Ni component.In addition,CeO 2 with high oxygen activity also promotes the dissociation of ethanol and vapor,overcoming the carbon deposition on the metal surface,and its interaction with Pt and Ni promotes the catalytic performance of the catalyst to some extent.
作者
孙晨
郑子良
李星
王诗瑶
吴旭
安霞
谢鲜梅
SUN Chen;ZHENG Ziliang;LI Xing;WANG Shiyao;WU Xu;AN Xia;XIE Xianmei(College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Translational Medicine Research Center,Shanxi Medical University,Taiyuan 030001,China)
出处
《太原理工大学学报》
CAS
北大核心
2018年第5期669-675,共7页
Journal of Taiyuan University of Technology
基金
国家自然科学基金资助项目(51541210)
山西省研究生教育创新项目(2016BY051)
山西省自然科学基金资助项目(201701D121042)
