The effect of carbon monoxide on the oligomerization of acetylene in hydrogen over a Ni/SiO2 catalyst

Selective Hydrogenation of Acetylene over Pd-In/Al2O3 Catalyst: Promotional Effect of Indium and Composition-Dependent Performance

“…To improve the selectivity of supported Pd catalysts in acetylene hydrogenation, carbon monoxide and some other molecules have been used as modifiers to compete with ethylene for adsorption sites and favor desorption of ethylene . However, the presence of CO reduces the surface concentration of hydrogen and facilitates the formation of green oil and the deactivation of catalysts. , Alternatively, a second metal has been introduced to modify the electronic and geometric structure of the Pd catalysts. − For example, Ag in the Pd catalyst was found to decrease the amount of absorbed hydrogen and suppress the diffusion of hydrogen from the bulk to the surface and as a result increase the selectivity to ethylene . Cu in the Pd catalyst was shown to decrease the number of multicoordination Pd sites which are responsible for the formation of ethane and the low selectivity to ethylene …”

“…12 However, the presence of CO reduces the surface concentration of hydrogen and facilitates the formation of green oil and the deactivation of catalysts. 13,14 Alternatively, a second metal has been introduced to modify the electronic and geometric structure of the Pd catalysts. 15−18 For example, Ag in the Pd catalyst was found to decrease the amount of absorbed hydrogen and suppress the diffusion of hydrogen from the bulk to the surface and as a result increase the selectivity to ethylene.…”

Enhanced selectivity in acetylenehydrogenation by ligand modified Pd/TiO2catalysts

“…2 The presence of CO together with a limited hydrogen supply are however linked to increased oligomer or ''green oil'' formation and accelerated catalyst deactivation. 3 Palladium catalysts used in this reaction have been modified by alloying, in particular with silver but other, non-precious metal catalysts have also been developed. 4 The origin of selectivity enhancement is attributed to either reduced active ensemble size effects or modified electronic characteristics of the active metal or more favourable hydrogenation to a particular intermediate.…”

A review of selective hydrogenation catalysts on active center and performance

“…反应条件: 0.5% C 2 H 2 , 5% H 2 , 50% C 2 H 4 , 44.5% He, 总流量 30 mL/min, 200℃ 随着 Pd 催化剂的发展, Ni 在选择加氢中的催化 性能研究虽然减少, 但由于其制造成本较低而依然 受到关注. Trimm 等制备了 MgAl 2 O 4 负载的 Ni 和 Ni-Zn 催化剂, 用于乙炔选择加氢 [71] , 并研究了 CO 对 Ni/SiO 2 催化性能的影响 [72,73] . DFT 计算表明, 向 Ni 中添加 Au、Ag 或 Cu 可以减弱乙炔的吸附, 从而 提高催化剂活性; 添加 Au 和 Ag 还有利于选择性的 提高 [74] .…”