Study On Functionalization Of Multi-walled Carbon Nanotubes And Its Effects On Catalytic Properties Of Ni/CNTs In Benzene Hydrogenation

Carbon nanotubes are considered to be attractive catalytic support owing to theiroutstanding mechanical characteristics such as high surface area coupled with hightensile strength, good thermal conductivity, and high electric conductivity.However, carbon nanotubes are highly polarizable, smooth-sided compounds withattractive interactions among tube-to-tube.Because of these conhesive forces, CNTsexist as bundled structure. This bundling phenomenon contributes to the bulkmaterials having limited solubility and poor dispersion in water. Also,the effectiveattachment of nickel nanoparticles uniformly dispersed onto CNTs remains aformidable challenge for the inertness of the CNT walls. In this paper, we used aserial of surfactants and nitric acid to functionalize the CNTs and to improve theCNTs dispersion in water thus to improve the attach efficiency of nanoparticles ontoCNTs. Ni/CNTs was prepared with functionalized CNTs,and benzene hydrogenationwas used as the p0be reaction.Effects of addition of Li, as well as functionalization of CNTs to Ni/CNTscatalyst's catalytic performance was investigated by means of FT-IR,TEM,XRD,TG,ICP,H₂-TPR,H₂-TPD and H₂-chemisorption.1,To realize the function of CNTs in Ni/CNTs catalyst for benzene hydrogenation,the Ni/CNTs,Ni/graphite,Ni/γ-Al₂O₃ were prepared with impregnation method andtheir catalytic activities in benzene hydrogenation were investigated. The results showthat Ni/CNTs catalyst has better catalytic activities and better surfur-resistance for the"hydrogen-spoillover "phenomenon on the CNTs.2,SLS,SDS,SDBS,Brij35,CTAB and HNO₃ were applied to preparewater-soluble CNTs., and the soluble property was characterized by UV-vismethod. The results show that the concentration was determined exactly with UV-vismethod.3,Effects of different functionalization of carbon nanotubes to catalytic propertiesof Ni/CNTs for benzene hydrogenation was investigated.,it shows that the catalyticactivity of Ni/CNTs in which CNTs modified by SLS was better than others.In detail, the effects on catalytic properties of Ni/CNTs catalyst in which CNTs modified viaSLS and nitric acid were studied, it was found that Ni/CNTs in which CNTs modifiedvia SLS exhibited better catalytic performance for the high dispersion.4,NiLi/CNTs catalysts with different amounts of Li were prepared by impregnationmethod where carbon nanotubes were functionalized by SLS. The results indicatedthat the addtion Of Li had an obvious impact on the catalytic performance ofNiLi/CNTs.A suitable concentration of Li could increase the fraction of metallic Ni-on the surface of the catalyst,thus increase the catalytic activity.It was found thatwhen the moral ratio-of Ni,Li is 10 tol,the moral conversion rate (â…©ï¼…) could reach100ï¼…at 413K.However, the continous addition of Li,the dispertion and thereducibility of Ni reduced on the CNTs,thus the activity reduced.