碳纳米管对非晶态NiB合金催化剂性能的影响

The Effects of CNTs on Performance of Amorphous NiB Catalyst

采用化学还原法制备了非晶态NiB合金,用CNTs-1、CNTs-2、γ-Al2O3作载体制备了负载型非晶态NiB合金催化剂.以乙炔选择性加氢为目标反应考察了催化活性和选择性,用TEM、TPD等方法对催化剂进行了表征.TEM结果表明,粒径为8～10 nm的NiB粒子均匀分散在CNTs-1外表面,大部分粒径为12～14 nm的NiB颗粒在CNTs-2内腔生长,而γ-Al2O3载体未能有效提高NiB分散度.用CNTs-1将NiB负载化,明显提高了NiB催化剂乙炔加氢活性.CNTs-1、CNTs-2和γ-Al2O3载体对比,CNTs-2作载体促进了催化剂对氢的吸附,减弱了乙炔的吸附,提高了加氢活性和乙烯选择性.

NiB and supported NiB amorphous alloy catalysts were prepared by chemical reduction method. The catalytic performance was evaluated during the selective hydrogenation of acetylene to ethylene. The properties of alloy were characterized by TEM and TPD. It can be seen from the TEM profiles that NiB particles whose diameter are 8 to 10 nm were dispersed on the outside of CNTs-1 homogeneously and 12 to 14 nm NiB were mainly formed in the inner of CNTs-2, however, agglomerate NiB granules were supported on they-Al2O3 carrier. Results showed the activity for half-hydrogenation of acetylene on NiB alloy was improved greatly because of the introduction of CNTs. The experimental data demonstrated that CNTs-2 promoted the adsorption of hydrogen and weakened the adsorption of acetylene on NiB amorphous alloy. Meanwhile, the hydrogenation activity and selectivity of ethylene were enhanced, as compared to CNTs-1 and y-Al2O3 supports.