碳纳米管负载非晶态NiP合金的催化性能

Catalytic Properties of NiP Amorphous Alloy Supported on Carbon Nanotubes

以碳纳米管(CNTs)为载体,用诱导-化学还原法制备了负载型非晶态 NiP 合金(NiP/CNTs)催化剂,并在相同条件下制备了非负载型非晶态 NiP 合金催化剂。用透射电子显微镜、X 射线衍射、等离子体发射光谱、低温氮吸附、X 射线光电子能谱和氢-程序升温脱附方法对这两种催化剂进行了表征。表征结果显示,NiP 合金和 NiP/CNTs 催化剂均具有非晶态结构;CNTs 的分散作用有效防止了 NiP 合金晶粒的团聚;NiP/CNTs 催化剂中的 CNTs 能将部分电子转移到 Ni 上,形成富电子 Ni;富电子 Ni 上形成的 Ni—H吸附键较弱。苯加氢实验结果表明,NiP/CNTs 催化剂的苯加氢活性较 NiP 合金催化剂低,但前者的比活性高,这与CNTs 载体的分散作用、CNTs 载体对 NiP 的给电子作用以及 CNTs 载体的贮氢性能有关。

A carbon nanotubes （CNTs） supported NiP amorphous alloy （NiP/CNTs） catalyst was prepared by induced reduction. Unsupported NiP amorphous alloy（NiP） catalyst was also prepared for comparison. Benzene hydrogenation was used as probe reaction for evaluation of catalytic activity. Effect of support CNTs on the catalyst activity was discussed based on characterizations, by means of TEM, XRD, ICP, low-temperature adsorption of nitrogen, XPS and H2-TPD. Both unsupported NiP and supported NiP existed in amorphous alloy state. Dispersing effect of CNTs strongly inhibited agglomeration of small NiP particles. In NiP/CNTs catalyst, the support donated electrons to Ni to form electron-rich Ni centers which led to forming weaker Ni-H adsorbent bonds. In comparison with unsupported NiP, activity of NiP/CNTs catalyst in benzene hydrogenation was low, but its specific activity was high, which attributed to dispersing effect, electron-donating effect and hydrogen-storage ability of support CNTs.