摘要
开发了一类以CNTs-γ-Al2O3复合材料为载体的高效催化甲苯加氢脱芳的Pt基催化剂.实验结果表明,适量添加少量的CNTs能显著提高Pt基催化剂催化甲苯加氢脱芳的活性.经组分优化的1.0%(质量分数)Pt/8%CNTs-γ-Al2O3催化剂上,在2.0MPa、363K、V(C7H8)∶V(H2)=1∶6.7、1 035L/(h·g)的反应条件下,甲苯转化率可达85.9%,时空收率为501.7g/(h·g),分别是相同条件下γ-Al2O3、CNTs、γ-Al2O3(商品)和SiO2负载催化剂上相应值(458.9、445.1、435.8和406.3g/(h·g))的1.09、1.13、1.15和1.24倍.进一步,联合多种谱学表征技术对催化剂进行表征,探讨CNTs对促进催化剂催化芳烃加氢的作用本质.研究结果表明,以CNTs-γ-Al2O3为载体的工作态Pt基催化剂上甲苯加氢脱芳的表观活化能与系列常规载体负载的参比体系上的相应值基本一致,表明少量CNTs的添加并不改变催化反应途径,但却提升了工作态催化剂表面具有催化活性的Pt0物种在表面总Pt量中所占比例;与γ-Al2O3负载的参比体系相比,CNTs-γ-Al2O3负载的Pt基催化剂增强的催化加氢活性可能源于CNTs对氢的适度吸附、活化及溢流性能.
A type of CNTs-γ-Al2 O3 hybrid material-supported Pt catalysts for the hydrogenation-dearomatization(HDA)of toluene was developed,which displayed excellent performance for HDA of toluene.Over the 1.0%Pt/8%CNTs-γ-Al2 O3 catalyst,under the reaction conditions of 2.0 MPa、363K、V(C7 H8)∶V(H2)=1∶6.7、GHSV=1 035L/(h·g),the observed conversion of toluene reached 85.9%,with the corresponding STY of being 501.7g/(h·g),this value was 1.09,1.13,1.15and 1.24times those of 1.0% Pt/γ-Al2 O3 、1.0%Pt/CNTs、1.0%Pt/γ-Al2 O3(goods)and 1.0%Pt/SiO2 catalysts,respectively,under the same reaction.Moreover, the impact of CNTs on the catalytic activity was investigated with a series of physico-chemical techniques,the characterized results showed that a small part of CNTs in the support of the catalyst did not cause a significant change in the apparent activation energy for the HDA reaction of toluene,but led to a certain increase in the molar percentage of catalytically active Pt-species(Pt0)in the total Pt-amount at the surface of the functioning catalyst.In addition,the Pt/CNTs and Pt/CNTs-γ-Al2 O3 catalyst could reversibly adsorb agreater amount of hydrogen under atmospheric pressure and temperatures ranging from room temperature to 773K.This unique feature would help to generate a microenvironment with higher stationary state concentration of active hydrogen-adspecies at the surface of the functioning catalyst.These effects favored increasing the rate of the HDA reaction of toluene.
出处
《厦门大学学报（自然科学版）》
CAS
CSCD
北大核心
2014年第1期71-77,共7页
Journal of Xiamen University：Natural Science
基金
国家重点基础研究发展计划(973)项目(2011CBA00500)
福建省自然科学基金(E0510001)
关键词
多壁碳纳米管
铂
纳米复合材料
甲苯
加氢脱芳
multi-walled carbon nanotube
platinum
nanohybrid material
toluene
hydrogenation-dearomatization
作者简介
hyli@xmu．edu．cn
