Selective hydrogenation of acetylene on SiO2 supported Ni-In bimetallic catalysts: Promotional effect of In
Selective hydrogenation of acetylene on SiO2 supported Ni-In bimetallic catalysts: Promotional effect of In
复制标题
SiO2负载Ni-In双金属催化剂上乙炔选择性加氢：In的促进作用
DOI：
10.1016/j.apsusc.2016.06.067
复制
发表时间：
2016-11-30
影响因子：
6.7
通讯作者：
Chen, Jixiang
中科院分区：
文献类型：
--
作者：
Chen, Yanjun;Chen, Jixiang
对Ni/SiO2和不同Ni/In比例的双金属NixIn/SiO2催化剂进行乙炔选择性加氢试验，并通过N-2吸附、H-2-TPR、XRD、TEM、XPS、H-2化学吸附、C2H4-TPD、NH3-TPD、FT-IR等手段对反应前后的物化性质进行表征。 吸附吡啶、TG/DTA 和拉曼。发现In对Ni/SiO2的性能有促进作用，具有合适的Ni/In比例的NixIn/SiO2比Ni/SiO2具有更高的乙炔转化率、乙烯选择性和催化剂稳定性。这归因于活性Ni原子与惰性In原子的几何隔离以及从In原子到Ni原子的电荷转移，这两者都有利于降低乙烯的吸附强度，抑制C-C氢解以及乙炔和中间体化合物的聚合。总体而言，Ni6In/SiO2和Ni10In/SiO2具有更好的性能。然而，随着In含量的增加，由于电荷从In原子转移到Ni原子，催化剂酸性增强，对C4+烃的选择性趋于增加。作为路易斯酸，In位点可以促进聚合。还分析了催化剂失活。我们认为 Ni/SiO2 失活主要归因于从金属 Ni 到碳化镍的相变。 In的引入抑制了碳化镍的形成。然而，随着In含量的增加，催化剂酸性增强，碳沉积成为NixIn/SiO2失活的主要原因。 (C) 2016 Elsevier B.V. 保留所有权利。
Ni/SiO2 and the bimetallic NixIn/SiO2 catalysts with different Ni/In ratios were tested for the selective hydrogenation of acetylene, and their physicochemical properties before and after the reaction were characterized by means of N-2-sorption, H-2-TPR, XRD, TEM, XPS, H-2 chemisorption, C2H4-TPD, NH3-TPD, FT-IR of adsorbed pyridine, and TG/DTA and Raman. A promotional effect of In on the performance of Ni/SiO2 was found, and NixIn/SiO2 with a suitable Ni/In ratio gave much higher acetylene conversion, ethylene selectivity and catalyst stability than Ni/SiO2. This is ascribed to the geometrical isolation of the reactive Ni atoms with the inert In ones and the charge transfer from the In atoms to Ni ones, both of which are favorable for reducing the adsorption strength of ethylene and restraining the C-C hydrogenolysis and the polymerizations of acetylene and the intermediate compounds. On the whole, Ni6In/SiO2 and Ni10In/SiO2 had better performance. Nevertheless, with increasing the In content, the selectivity to the C4+ hydrocarbons tended to increase due to the enhanced catalyst acidity because of the charge transfer from the In atoms to Ni ones. As the Lewis acid ones, the In sites could promote the polymerization. The catalyst deactivation was also analyzed. We propose that the Ni/SiO2 deactivation is mainly attributed to the phase change from metallic Ni to nickel carbide. The introduction of In inhibited the formation of nickel carbide. However, as the In content increased, the carbonaceous deposit became the main reason for the NixIn/SiO2 deactivation due to the enhanced catalyst acidity. (C) 2016 Elsevier B.V. All rights reserved.