采用程序升温脱附(TPD)、Boehm滴定以及质量滴定(Mass titration)等方法分析了多壁碳纳米管(MWCNT)经过浓硝酸改性处理前后的表面酸性和酸性分布;同时运用XRD技术研究了碳纳米管负载Co-Mo催化剂的表面物种和活性组分的分散;并在高压微型反应器中,以二苯并噻吩(DBT)为模型化合物,对碳纳米管负载的Co-Mo催化剂体系进行了加氢脱硫(HDS)活性评价,以期揭示碳纳米管的表面修饰对其负载Co-Mo催化剂HDS性能的影响.研究结果表明:MWCNT表面呈一定的碱性,通过浓硝酸化学修饰以后,反而呈现较强的酸性,并且随着酸处理时间的延长,表面的酸性进一步增加.如,M-MWCNT-6(酸化6 h)表面总酸量为1.29×10-3 mol/g,M-MWCNT-24(酸化24 h)表面总酸量为2.46×10-3 mol/g.酸改性提高了Co-Mo催化剂在MWCNT表面的分散程度,以致Co-Mo/MWCNT催化剂的HDS活性和选择性明显高于Co-Mo/γ-Al2O3催化体系.然而,Co-Mo/M-MWCNT-6的HDS活性以及选择性与Co-Mo/MWCNT相差不多,略有降低,但是仍比Co-Mo/γ-Al2O3催化体系的HDS活性高.Co-Mo/M-MWCNT-24催化剂的HDS活性降低很多,并且催化性能发生了很大改变,产物中出现了大量的副产物1,2-二苯基乙烷.表明,深度酸化改性反而不利于提高碳纳米管负载Co-Mo催化体系的HDS活性.
参考文献
| [1] | Iijima S .Helical Microtubules of Griphitic Carbon[J].Nature,1991,354(6324):56-58. |
| [2] | Amerinecks S;Zhang X B;Bernaerts D et al.A formation mechanism for catalytically grown helix graphite nanotube[J].Science,1994,265:635-639. |
| [3] | 戴贵平,赵志刚,刘敏,侯鹏翔,王茂章,成会明.纳米碳管储氢机理的电化学研究[J].新型炭材料,2002(04):49-52. |
| [4] | 戴贵平,刘敏,王茂章,成会明.纳米碳管电化学储氢的研究进展[J].新型炭材料,2002(03):70-74. |
| [5] | 张滨,刘畅,成会明,才庆魁.纳米碳管内包覆外来物质的研究进展[J].新型炭材料,2003(03):174-180. |
| [6] | 雷中兴,李轩科,汪厚植,洪学勤,陈家唯.包覆纳米镍粒子的碳纳米管磁性研究（英文）[J].新型炭材料,2002(04):67-70. |
| [7] | 王敏炜,李凤仪,彭年才.碳纳米管--新型的催化剂载体[J].新型炭材料,2002(03):75-79. |
| [8] | 沈建其,何少龙,王新庆,王淼.单壁纳米碳管储氢机制研究[J].新型炭材料,2001(02):24-26,65. |
| [9] | 李峰,白朔,成会明.纳米碳管[J].新型炭材料,2000(03):79-80. |
| [10] | Philippe Serp;Massimiliano Corrias;Philippe Kalck .Carbon nanotubes and nanofibers in catalysis[J].Applied Catalysis, A. General: An International Journal Devoted to Catalytic Science and Its Applications,2003(2):337-358. |
| [11] | Joong S N;James A S .Effect of HNO3 treatment on the surface acidity of activated carbons[J].Carbon,1990,28(05):675-682. |
| [12] | Tsang S C;Chen Y K;Harris P J F et al.A simple chemical method of opening and filling carbon nanotube[J].Nature,1994,372:159-162. |
| [13] | Suzana Z;Nikola K .Application of mass titration on the point of zero charge determination[J].Journal of Colloid and Interface Science,1992,149(01):233-240. |
| [14] | Suvanto M;Rty J;Pakkanen T A .Catalytic activity of carbonyl precursor based W/Al2O3 and CoMo/Al2O3 catalysts in the hydrodesulfurization of thiophehe[J].Applied Catalysis A:General,1999,181:189-199. |
| [15] | Jacek J;Teresa J B;James A S .inverse gas chromatographic study of activated carbons: the effect of controlled oxidation on microstructure and surface chemical functionality[J].Journal of Colloid and Interface Science,1992,151(02):433-444. |
| [16] | Fabish T J F;Schleifer D E .Surface chemistry and the carbon black work function[J].Carbon,1984,22(01):19-38. |
| [17] | Corapcioglu M O;Huang C P .The surface acidity and characterization of some commercial activated carbons[J].Carbon,1987,25(04):569-578. |
| [18] | Barton SS.;Halliop E.;Macdonald JAF.;Evans MJB. .ACIDIC AND BASIC SITES ON THE SURFACE OF POROUS CARBON[J].Carbon: An International Journal Sponsored by the American Carbon Society,1997(9):1361-1366. |
| [19] | Leon Y;Leon C A;Solar J M et al.Evidence of the protonation of basal plane sites on carbon[J].Carbon,1992,30(05):797-811. |
| [20] | Grzechowiak J R;Rynkowski J;Wereszczako-Zielifiska I .Catalytic hydrotreatment on allumina-titania supported NiMo sulfides[J].Catalysis Today,2001,65(3-4):225-231. |
| [21] | Shim J W;Park S J;Ryu S K .Effect of modification with HNO3 and NaOH on metal adsorption by pitch-based active carbon fibers[J].Carbon,2001,39:1635-1642. |
| [22] | 李忠瑞,伏义路,姜明,陈东明.活性炭担载的钾钼合成醇催化剂[J].燃料化学学报,1999(05):467-471. |
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