Effect of W addition on the catalytic properties of Mo/HZSM-5 catalyst in methane non-oxidative dehydroaromatization
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摘要: 采用浸渍法制备了Mo/HZSM-5、Mo-W/HZSM-5和W/HZSM-5三种催化剂。通过XRD、BET、Py-FTIR、H2-TPR、XPS、TEM、NH3-TPD、TPO、TG和Raman等技术对催化剂的物化性质进行表征，并考察其在甲烷无氧芳构化反应中的催化性能。结果表明，相比于Mo/HZSM-5，Mo-W/HZSM-5催化剂表现出更高的CH4转化率、芳烃收率以及催化稳定性。H2-TPR和XPS结果表明，Mo-W/HZSM-5中存在更易被还原为W4+的正八面体（WO6）n-前驱体，反应过程中W4+的形成有助于提高CH4转化率。同时，积炭表征结果表明，石墨型积炭是导致Mo/HZSM-5催化剂快速失活的主要原因，W掺杂可以抑制Mo-W/HZSM-5催化剂上石墨型积炭的形成，进而提高催化剂的稳定性。Abstract: Mo/HZSM-5, Mo-W/HZSM-5 and W/HZSM-5 catalysts were prepared via a conventional impregnation method. The catalysts were characterized by means of XRD, BET, Py-FTIR, H2-TPR, XPS, TEM, NH3-TPD, TPO, TG and Raman, and were evaluated in methane non-oxidative dehydroaromatization(MDA). Compared with Mo/HZSM-5, the CH4 conversion, aromatics yield and catalytic stability were improved by W addition for Mo-W/HZSM-5 in MDA reaction. H2-TPR and XPS results indicated that the octahedral (WO6)n- groups existed in Mo-W/HZSM-5 were more easily reduced to W4+-containing species in MDA reaction in comparison with W/HZSM-5, and W4+-containing species was correlated with the high MDA activity. At the same time, it is found that graphitic-like coking is the main reason of catalyst deactivation for Mo/HZSM-5, and this coking over Mo-W/HZSM-5 catalyst can be inhibited by W addition during MDA.
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Key words:
- non-oxidative dehydroaromatization /
- molybdenum /
- coking /
- tungsten
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图 1 三种催化剂在MDA反应中的催化性能
Figure 1 Catalytic performances of catalysts in MDA reaction
(reaction conditions: p=0.1 MPa, t=700 ℃, GHSV=1 500 mL/(gcat·h)
图 3 载体和新鲜催化剂的NH3-TPD和吡啶红外光谱谱图
Figure 3 NH3-TPD (a) and Py-FTIR (b) profiles of samples
图 6 反应后催化剂的TG曲线和TPO谱图
Figure 6 TG curves (a) and TPO profiles (b) of catalysts after 10 h reaction
图 8 催化剂反应前后的TEM照片
Figure 8 TEM images of fresh Mo/HZSM-5(a), Mo-W/HZSM-5(b) and W/HZSM-5 catalysts(c) and used Mo/HZSM-5(d), Mo-W/HZSM-5(e) and W/HZSM-5(f) after 10 h reaction
表 1 催化剂的孔结构和酸性数据
Table 1 Textural and acidic properties of catalysts
Catalyst HZSM-5 Mo/HZSM-5 Mo-W/HZSM-5 W/HZSM-5 Content w/%a Mo - 7.03 3.32 - W - - 2.07 5.04 Textural propertiesb ABET/(m2·g-1) 416 330 324 344 Amicro/(m2·g-1) 322 256 249 272 v/(cm3·g-1) 0.27 0.23 0.23 0.24 vmicro/(cm3·g-1) 0.13 0.10 0.10 0.10 Acidic properties/(μmol·g-1)c total 545 382 377 376 weak 301 222 234 187 strong 244 160 143 189 B/L(acid ratio)d 150 ℃ 2.24 2.05 1.55 2.02 250 ℃ 3.03 2.91 2.13 2.76 350 ℃ 2.94 3.03 2.27 2.84 a: measured by ICP；b: volume absorbed at p/p0=0.99；c: measured by NH3-TPD；d : determined by Py-FTIR 
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表 2 反应后催化剂的TG、TPO和Raman表征
Table 2 TG, TPO and Raman results of coked catalysts
Coked catalysts Oxidative peak position t /℃ Amount of coking/(mg·gcat-1) Degree of graphitization ID/IG low high low high total Mo/HZSM-5 473 548 33.8 62.3 96.1 1.096 Mo-W/HZSM-5 489 556 31.7 61.7 93.4 1.129 W/HZSM-5 501 577 16.2 72.2 88.4 1.159
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[1] SPIVEY J J, HUTCHINGS G. Catalytic aromatization of methane[J]. Chem Soc Rev, 2014, 43(3):792-803. doi: 10.1039/C3CS60259A [2] 王华, 刘中民.甲烷直接转化研究进展[J].化学进展, 2004, 16(4):593-602. http://d.wanfangdata.com.cn/Periodical/hxjz200404014WANG Hua, LIU Zhong-min. Progress in direct conversion of methane[J]. Prog Chem, 2004, 16(4):593-602. http://d.wanfangdata.com.cn/Periodical/hxjz200404014 [3] WANG L S, TAO L X, XIE M S, XU G F, HUANG J S, XU Y D. Dehydrogenation and aromatization of methane under non-oxidizing conditions[J]. Catal Lett, 1993, 21(1):35-41. https://academic.oup.com/nsr [4] KARAKAYA C, KEE R J. Progress in the direct catalytic conversion of methane to fuels and chemicals[J]. Prog Energy Combust Sci, 2016, 55:60-97. doi: 10.1016/j.pecs.2016.04.003 [5] GUO X G, FANG G Z, LI G, MA H, FAN H J, YU L, MA C, WU X, DENG D H, WEI M M, TAN D L, SI R, ZHANG S, LI J Q, SUN L T, TANG Z C, PAN X L, BAO X H. Direct, nonoxidative conversion of methane to ethylene, aromatics, andhydrogen[J]. Science, 2014, 344(2):616-619. http://europepmc.org/abstract/MED/24812398 [6] SCHWACH P, PAN X L, BAO X H. Direct conversion of methane to value-added chemicals overheterogeneous catalysts:Challenges and prospects[J]. Chem Rev, 2017, 177:8497-8520. http://www.ncbi.nlm.nih.gov/pubmed/28475304 [7] LIU H M, SU LL, WANG H X, SHEN W J, BAO X H, XU Y D. The chemical nature of carbonaceous deposits and their role in methane dehydro-aromatization on Mo/MCM-22 catalysts[J]. Appl Catal A:Gen, 2002, 236(1):263-280. http://www.sciencedirect.com/science/article/pii/S0926860X02002934 [8] TEMPELMAN C H L, HENSEN E J M. On the deactivation of Mo/HZSM-5 in the methane dehydroaromatizationreaction[J]. Appl Catal B:Environ, 2015, 176/177:731-739. doi: 10.1016/j.apcatb.2015.04.052 [9] 马记源, 陆江银, 袁钊, 王春晓. Co改性Mo/HZSM-5催化剂的甲烷无氧芳构化催化性能研究[J].石油炼制与化工, 2013, 44(11):29-34. doi: 10.3969/j.issn.1005-2399.2013.11.006MA Ji-yuan, LU Jiang-yin, YUAN Zhao, WANG Chun-xiao. Methane dehydroaromatization over cobalt modified Mo/HZSM-5 catalysts in absence of oxidants[J]. Chin Petrol Process Petrochem Technol, 2013, 44(11):29-34. doi: 10.3969/j.issn.1005-2399.2013.11.006 [10] 马记源, 张航飞, 尹金莲, 周蓉, 陆江银. Ni改性Mo-Co/HZSM-5催化剂在甲烷无氧芳构化中的研究[J].天然气化工(C1化学与化工), 2016, 41(2):19-24. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=trqh201602006&dbname=CJFD&dbcode=CJFQMA Ji-yuan, ZHANG Hang-fei, YIN Jin-lian, ZHOU Rong, LU Jiang-yin. Methane dehydroaromatization over Ni modified Mo-Co/HZSM-5 catalysts[J]. Nat Gas Chem Ind, 2016, 41(2):19-24. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=trqh201602006&dbname=CJFD&dbcode=CJFQ [11] 刘红梅, 申文杰, 包信和, 徐奕德. Co助剂对甲烷脱氢芳构化反应中Mo/MCM-22催化剂积碳行为的影响[J].催化学报, 2004, 25(6):495-500. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=chua200406015&dbname=CJFD&dbcode=CJFQLIU Hong-mei, SHEN Wen-jie, BAO Xin-he, XU Yi-de. Effect of Co additive on the formation of carbon deposit on Mo/MCM-22 catalyst for methane dehydro-aromatization[J]. Chin J Catal, 2004, 25(6):495-500. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=chua200406015&dbname=CJFD&dbcode=CJFQ [12] LIU B S, YANG Y, SAYARI A. Non-oxidative dehydroaromatization of methane over Ga-promoted Mo/HZSM-5-based catalysts[J]. Appl Catal A:Gen, 2001, 214(1):95-102. doi: 10.1016/S0926-860X(01)00470-7 [13] WONG S T, XU Y D, WANG L S, LIU S T, LI G J, XIE M S, GUO X X. Methane and ethane activation without adding oxygen:promotional effect of W in Mo-W/HZSM-5[J]. Catal Lett, 1996, 38(1):39-43. doi: 10.1007/BF00806897 [14] KOSINOV N, COUMANS F J A G, LI G N, USLAMIN E, MEZARI B, WIJPKEMA A S G, PIDKO E A, HENSEN E J M. Stable Mo/HZSM-5 methane dehydroaromatization catalysts optimized for igh-temperature calcinations-regeneration[J]. J Catal, 2017, 346:125-133. doi: 10.1016/j.jcat.2016.12.006 [15] 刘恒, 阚秋斌.介孔材料为硅源合成多级孔Mo/H-IM-5催化剂及其在甲院无氧芳构化反应中的应用[J].燃料化学学报, 2016, 44(11):1380-1387. doi: 10.3969/j.issn.0253-2409.2016.11.015LIU Heng, KAN Qiu-bin. Synthesis ofhierarchical Mo/H-IM-5 catalysts by using mesoporous material as the silica source and its application in methane non-oxidative aromatization[J]. J Fuel Chem Technol, 2016, 44(11):1380-1387. doi: 10.3969/j.issn.0253-2409.2016.11.015 [16] ZENG J L, XIONG Z T, ZHANG H B, LIN G D, TSAI K R. Nonoxidative dehydrogenation and aromatization of methane over W/HZSM-5-based catalysts[J]. Catal Lett, 1998, 53(1):119-124. doi: 10.1023/A%3A1019033201075 [17] 熊智涛, 曾金龙, 张鸿斌, 林国栋, 蔡启瑞.甲烷脱氢芳构化W/HZSM-5基催化剂的制备[J].催化学报, 1999, 20(1):35-40. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=chua901.009&dbname=CJFD&dbcode=CJFQXIONG Zhi-tao, ZENG Jin-long, ZHANG Hong-bin, LIN Guo-dong, CAI Qi-rui. Study of preparation of W/HZSM-5-based catalysts for non-oxidative dehydro-aromatization of methane[J]. Chin J Catal, 1999, 20(1):35-40. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=chua901.009&dbname=CJFD&dbcode=CJFQ [18] 曾金龙, 熊智涛, 于腊佳, 林国栋, 张鸿斌.甲烷脱氢芳构化W/HZSM-5基催化剂EPR研究[J].厦门大学学报(自然版), 1998, 37(4):532-536. http://www.cqvip.com/qk/95448X/199804/3132882.htmlZENG Jin-long, XIONG Zhi-tao, YU La-jia, LIN Guo-dong, ZHANG Hong-bin. EPR spectroscopic characterization of W/HZSM-5 based catalysts for dehydro-aromatization of methane[J]. J Xiamen Univ (Nat Sci), 1998, 37(4):532-536. http://www.cqvip.com/qk/95448X/199804/3132882.html [19] 黄利强, 曾金龙, 林国栋, 袁友珠, 张鸿斌.甲烷无氧脱氢芳构化双促进W/MCM-22基催化剂研究[J].化学学报, 2004, 62(18):1706-1712. doi: 10.3321/j.issn:0567-7351.2004.18.007HUANG Li-qiang, ZENG Jin-long, LIN Guo-dong, YUAN You-zhu, ZHANG Hong-bin. Study on doubly promoted W/MCM-22-based catalysts for dehydro-aromatization of CH4 in the absence of O2[J]. Acta Chim Sin, 2004, 62(18):1706-1712. doi: 10.3321/j.issn:0567-7351.2004.18.007 [20] 黄利强, 林种玉, 于腊佳, 廖新丽, 曾金龙, 张鸿斌.甲烷无氧脱氢芳构化W/MCM-22基催化剂积炭的表征研究[J].厦门大学学报(自然版), 2005, 44(1):71-76. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=xdzk20050100i&dbname=CJFD&dbcode=CJFQHUANG Li-qiang, LIN Zhong-yu, YU La-jia, LIAO Xin-li, ZENG Jin-long, ZHANG Hong-bin. Characterization of carbon deposits on W/MCM-22-based catalysts for dehydro-aromatization of CH4 in absence of O2[J]. J Xiamen Univ (Nat Sci), 2005, 44(1):71-76. http://kns.cnki.net/KCMS/detail/detail.aspx?filename=xdzk20050100i&dbname=CJFD&dbcode=CJFQ [21] HUANG L Y, XU H, LI Y P, LI H M, CHENG X N, XIA J X, XU Y G, CAI G B. Visible-light-induced WO3/g-C3N4 composites with enhanced photocatalytic activity[J]. Dalton Trans, 2013, 42(24):8606-8616. doi: 10.1039/c3dt00115f [22] HUANG X, SUN N N, XUE G X, WANG C Z, ZHAN H J, ZHAO N, XIAO F K, WEI W, SUN Y H. Effect of pore geometries on the catalytic properties of NiO-Al2O3 catalysts in CO2 reforming of methane[J]. Rsc Adv, 2015, 5(27):21090-21098. doi: 10.1039/C4RA16313C [23] HUANG X, XUE G X, WANG C Z, ZHAO N, SUN N N, WEI W, SUN Y H. Highly stable mesoporous NiO-Y2O3-Al2O3 catalysts for CO2 reforming of methane:Effect of Ni embedding and Y2O3 promotion[J]. Catal Sci Technol, 2015, 6(2):449-459. http://pubs.rsc.org/en/content/articlepdf/2016/cy/c5cy01171j [24] SONG Y, ZHANG Q, XU Y B, ZHANG Y, KOICHIM, ZHANG Z G. Coke accumulation and deactivation behavior of microzeolite-based Mo/HZSM-5 in the non-oxidative methane aromatization under cyclic CH4-H2 feed switch mode[J]. Appl Catal A:Gen, 2017, 530:12-20. doi: 10.1016/j.apcata.2016.11.016 [25] QUEK X Y, LIU D P, WEI N E C, WANG H, CHEN Y, YANG Y H. Nickel-grafted TUD-1 mesoporous catalysts for carbon dioxide reforming of methane[J]. Appl Catal B:Environ, 2010, 95(3):374-382. http://www.sciencedirect.com/science/article/pii/S0926337310000305 [26] HUANG X, JI C C, WANG C Z, XIAO F K, ZHAO N, SUN N N, WEI W, SUN Y H. Ordered mesoporous CoO-NiO-Al2O3bimetallic catalysts with dual confinement effects for CO2 reforming of CH4[J]. Catal Today, 2017, 281:241-249. doi: 10.1016/j.cattod.2016.02.064 [27] MATUS E V, ISMAGILOV I Z, SUKHOVA O B, ZAIKOVSKII V I, TSIKOZA L T, ISMAGILOV Z R. Study of methane dehydroaromatization on impregnated Mo/ZSM-5 catalysts and characterization of nanostructured molybdenum phases and carbonaceous deposits[J]. Ind Eng Chem Res, 2007, 46(12):4063-4074. doi: 10.1021/ie0609564 [28] LIU B S, JIANG L, SUN H, AU C T. XPS, XAES, and TG/DTA characterization of deposited carbon in methane dehydroaromatization over Ga-Mo/ZSM-5 catalyst[J]. Appl Surf Sci, 2007, 253(11):5092-5100. doi: 10.1016/j.apsusc.2006.11.031 -
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