多功能Pt-Nb/MOR催化剂上C-C裂解促进木质素转化为单体环烷烃

doi:10.1016/S1872-2067(24)60260-3

摘要/Abstract

摘要：

木质素作为自然界中广泛存在的富含苯环结构的生物质资源, 其解聚与增值利用得到了广泛的关注. 木质素主要由芥子醇、松柏醇、香豆醇三种单体结构通过不同的C-O和C-C键链接形成三维立体网状结构, 在植物细胞壁结构中起到重要的支撑作用. 其中C-O键的比例约为70%, C-C键所占比例约为30%. 通过C-O和C-C键的裂解将木质素高效地转化为酚类、芳烃和单环烷烃吸引了众多研究者的兴趣, 但由于C-C键具有较高的键能和解离能, 其裂解具有极大的挑战性. 我们先前的研究表明, NbO_x基催化剂由于其酸性位点的存在而具有优异的C_Ar-C键解离能力, 得以突破木质素单体的收率的极限. 而分子筛作为一种常见的酸性载体, 将其引入多功能催化剂设计中有望在减少Nb用量、降低催化剂制备成本方面起到效果.
本文提出了一种经济型的多功能Pt-Nb/MOR催化剂, 首先选择键能最高的5-5’键模型化合物邻苯基苯酚作为底物, 对催化剂中Nb和Pt含量进行了优化, 发现2Pt-2Nb/MOR催化剂活性最佳. 反应路径研究表明, 与传统NbO_x基催化剂不同, 该催化体系中双环己烷是重要的中间体, 在环加氢得到该中间体后经过C_sp₃-C_sp₃裂解路径得到单体环烷烃. 含有不同C-C键和不同取代基的模型化合物在2Pt-2Nb/MOR催化剂上均能达到60%以上的单体收率. 在以有机桦木木质素为底物的解聚和加氢脱氧反应生成单环烷烃的过程中, 2Pt-2Nb/MOR催化剂上有147%的单体收率, 与相应贵金属负载量的NbO_x基催化剂活性相当, 且成本更低. 以上述有机桦木木质素为底物的循环稳定性实验表明, 催化剂有良好的循环稳定性, 循环使用三次后单体收率从147%下降至130%, 套用过程中产生的积碳可能是导致其失活的主要原因. 煅烧再生后的催化剂单体收率恢复到了145%, 证明了催化剂的良好稳定性. 将该催化剂应用在不同种类的木质素上, 质量收率均高于20 wt%, 摩尔收率均高于140%, 证明该催化剂具有良好的普适性, 能够有效地促进各种木质素中C-C键的裂解以得到环烷烃类单体产物. 2Pt-2Nb/MOR催化剂表征结果表明, 在Pt/MOR中掺杂Nb增强了Pt的金属性, 从而加强了催化剂对氢气的活化能力; 另外, Nb的引入也增加了MOR载体的酸度, 这些均有利于C_sp₃-C_sp₃键氢解得到单体.
综上, 本文设计了一种低成本、高活性的2Pt-2Nb/MOR多功能催化剂, 能够在相对温和的条件下从木质素中解聚获得高收率的单体, 为以后木质素增值催化剂的设计提供了新思路.

关键词: 木质素, 单环烷烃, C-C键裂解, Pt-Nb/MOR催化剂

Abstract:

The efficient conversion of lignin into mono-cycloalkanes via both C-O and C-C bonds cleavage are attractive, but challenging due to the high C-C bond dissociation energy. Previous studies have demonstrated that NbO_x-based catalysts exhibited exceptional capabilities for C_Ar-C bond cleavage and broken the limitation of lignin monomers. In this work, we presented an economical multifunctional Pt-Nb/MOR catalyst that achieved an impressive monomer yield of 147% during the depolymerization and hydrodeoxygenation of lignin into mono-cycloalkanes. Reaction pathway studies showed that unlike traditional NbO_x-based catalytic system, bicyclohexane was an important intermediate in this system and followed the C_sp₃-C_sp₃ cleavage pathway after complete cyclic-hydrogenation. Deep investigations demonstrated that the doping of Nb in Pt/MOR not only enhanced the activation of hydrogen by Pt, but also increased the acidity of MOR, both of these are favor for the hydrogenolytic cleavage of C_sp₃-C_sp₃ bonds. This work provides a low-cost catalyst to obtain high-yield monomers from lignin under relatively mild conditions and would help to design catalysts with higher activity for the valorization of lignin.

Key words: Lignin, Mono-cycloalkanes, C-C bond cleavage, Pt-Nb/MOR catalyst

郭芷若, 刘晓晖, 郭勇, 王艳芹. 多功能Pt-Nb/MOR催化剂上C-C裂解促进木质素转化为单体环烷烃[J]. 催化学报, 2025, 71: 285-296.

Zhiruo Guo, Xiaohui Liu, Yong Guo, Yanqin Wang. Enhanced conversion of lignin into mono-cycloalkanes via C-C bonds cleavage over multifunctional Pt-Nb/MOR catalyst[J]. Chinese Journal of Catalysis, 2025, 71: 285-296.

×
扫码分享

导出引用管理器 EndNote|Ris|BibTeX

链接本文: https://www.cjcatal.com/CN/10.1016/S1872-2067(24)60260-3

https://www.cjcatal.com/CN/Y2025/V71/I4/285

图/表 14

Table 1 Catalytic performance of various 2Pt-2Nb/zeolite catalysts.

Entry	Catalyst	Conversion /%		Yield/%
Entry	Catalyst	Conversion /%	2	3	4	5	6	7	8	9	Monomers
1	2Pt-2Nb/MOR	99.9	—	1.7	4.7	5.1	48.2	8.5	19.1	3.5	75.8
2	2Pt-2Nb/β₄₀	99.9	—	—	3.5	—	38.5	9.6	18.3	—	66.4
3	2Pt-2Nb/β₂₅	99.9	—	—	10.7	—	22.6	2.5	11.8	—	36.9
4	2Pt-2Nb/ZSM-5	56.1	6.6	15.5	5.9	—	19.7	1.0	3.1	1.7	23.8
5	2Pt-2Nb/USY	78.1	2.7	17.5	6.0	1.3	18.4	1.6	4.5	15.2	24.5
6	2Pt/Nb₂O₅	99.9	1.2	24.2	14.6	8.9	29.3	12.5	1.4	0.2	43.2
7	2Pt/NbOPO₄	99.9	1.4	20.1	17.6	7.6	37.1	11.7	1.7	0.4	50.5

Table 2 Catalytic performance of Pt-Nb/MOR catalysts with different metal contents.

Entry	Catalysts	Conversion /%		Yield/%
Entry	Catalysts	Conversion /%	2	3	4	5	6	7	8	9	Monomers
1	2Pt-2Nb	99.9	—	1.7	4.7	5.1	48.2	8.5	19.1	3.5	75.8
2	2Pt	99.9	12.7	10.0	17.9	6.5	20.7	5.2	6.8	13.8	32.7
3	2Pt-1Nb	99.9	2.4	2.7	9.14	4.2	33.4	8.1	11.0	17.9	52.5
4	2Pt-5Nb	99.9	—	3.8	17.6	13.0	30.1	12.9	9.8	7.1	52.8
5	2Pt-10Nb	99.9	—	13.0	12.6	4.1	24.8	15.2	9.6	15.7	49.6
6	1Pt-2Nb	89.4	25.1	20.7	8.1	2.4	12.5	9.0	2.1	4.2	23.6
7	0.5Pt-2Nb	85.5	36.7	9.6	2.4	0.7	8.9	6.8	1.5	11.7	17.2
8	2Nb	25.0	17.9	—	—	—	—	—	—	—	—

Fig. 1. Time course profiles of 1. Reaction conditions: 1.3 mmol 1, 0.05 g 2Pt-2Nb, 5 mL octane, 0.5 MPa H2, 260 °C.

Fig. 2. Conversion and monomer yield when using phenylcyclohexane (3) as substrates over different catalysts. Reaction conditions: 1.3 mmol phenyl-cyclohexane, 0.05 g catalysts, 5 mL octane, 0.5 MPa H2, 260 °C, 1 h.)

Fig. 3. Conversion and monomer yield when using bicyclohexane (4) as substrates over different catalysts. Reaction conditions: 1.3 mmol bicyclohexane, 0.05 g catalysts, 5 mL Octane, 0.5 MPa H2, 260 °C, 1 h. a 0.5 h.

Scheme 1. Proposed reaction pathway for the cleavage of C-C linkage.

Fig. 4. Conversion and monomer yield of model compounds over 2Pt-2Nb. Reaction conditions: 1.3 mmol substrate, 0.05 g catalysts, 5 mL octane, 0.5 MPa H2, 260 °C, 12 h. a 24 h.

Fig. 5. Catalytic performance on lignin over 2Pt-2Nb. Reaction conditions: 0.2 g lignin, 0.2 g 2Pt-2Nb/MOR, 5 mL octane, 0.5 MPa H2, 300 °C, 40 h. a 0.2 g 2Pt/NbOPO4 as catalyst.

Fig. 6. Stability test of 2Pt-2Nb. Reaction conditions: 0.2 g Birch lignin, 0.2 g 2Pt-2Nb/MOR, 5 mL octane, 0.5 MPa H2, 300 °C, 40 h.

Table 3 Metal contents, BET surface area, pore volume, pore size and Pt dispersion of catalysts.

Catalysts	Pt content ^a (wt%)	Nb content ^a (wt%)	A_BET (m²/g)	V_Total (cm³/g)	Average pore size (nm)	Pt dispersion ^b (%)
MOR	—	—	409.6	0.33	3.3	—
2Pt	1.7	—	303.6	0.16	2.1	32.9
2Pt-2Nb	1.7	2.1	395.5	0.21	2.1	30.5
2Pt-2Nb-Reuse 3	1.5	2.0	394.1	0.21	2.1	27.1

Fig. 7. TEM images of 2Pt (a,b) and 2Pt-2Nb (c,d).

Fig. 8. Pt 4d5/2 XPS spectra (a) and CO-DRIFT spectra (b) of 2Pt and 2Pt-2Nb catalysts.

Fig. 9. Reaction order of H2 (a) and bicyclohexane (b) on 2Pt-2Nb. Reaction order of H2 (c) and bicyclohexane (d) on 2Pt.

Fig. 10. Py-IR spectra of MOR, 2Pt and 2Pt-2Nb catalysts at 100 °C.

参考文献

[1]	R. Rinaldi, R. Jastrzebski, M. T. Clough, J. Ralph, M. Kennema, P. C. A. Bruijnincx, B. M. Weckhuysen, Angew. Chem. Int. Ed., 2016, 55, 8164-8215.
[2]	Z. Zhang, J. Song, B. Han, Chem. Rev., 2016, 117, 6834-6880.
[3]	Y. Guo, Y. Jing, Q. Xia, Y. Wang, Acc. Chem. Res., 2022, 55, 1301-1312.
[4]	A. J. Ragauskas, G. T. Beckham, M. J. Biddy, R. Chandra, F. Chen, M. F. Davis, B. H. Davison, R. A. Dixon, P. Gilna, M. Keller, P. Langan, A. K. Naskar, J. N. Saddler, T. J. Tschaplinski, G. A. Tuskan, C. E. Wyman, Science, 2014, 344, 1246843.
[5]	C. Xu, R. A. D. Arancon, J. Labidi, R. Luque, Chem. Soc. Rev., 2014, 43, 7485-7500.
[6]	C. Li, X. Zhao, A. Wang, G. W. Huber, T. Zhang, Chem. Rev., 2015, 115, 11559-11624.
[7]	F. S. Chakar, A. J. Ragauskas, Ind. Crops. Prod., 2004, 20, 131-141.
[8]	A. Rahimi, A. Ulbrich, J. J. Coon, S. S. Stahl, Nature, 2014, 515, 249-252.
[9]	Y. Li, L. Shuai, H. Kim, A. H. Motagamwala, J. K. Mobley, F. Yue, Y. Tobimatsu, D. Havkin-Frenkel, F. Chen, R. A. Dixon, J. S. Luterbacher, J. A. Dumesic, J. Ralph, Sci. Adv., 2018, 4, eaau2968.
[10]	Y, Liao, S.-F. Koelewijn, G. Van den Bossche, J. Van Aelst, S. Van den Bosch, T. Renders, K. Navare, T. Nicolaï, K. Van Aelst, M. Maesen, H. Matsushima, J. M. Thevelein, K. Van Acker, B. Lagrain, D. Verboekend, B. F. Sels, Science, 2020, 367, 1385-1390.
[11]	F. Cheng, C. E. Brewer, Renewable Sustainanle Energy Rev., 2017, 72, 673-722.
[12]	Q. Meng, J. Yan, R. Wu, H. Liu, Y. Sun, N. Wu, J. Xiang, L. Zheng, J. Zhang, B. Han, Nat. Commun., 2021, 12, 4534.
[13]	M. L. Stone, M. S. Webber, W. P. Mounfield, D. C. Bell, E. Christensen, A. R. C. Morais, Y. Li, E. M. Anderson, J. S. Heyne, G. T. Beckham, Y. Román-Leshkov, Joule, 2022, 6, 2324-2337.
[14]	Q. Xia, Z. Chen, Y. Shao, X. Gong, H. Wang, X. Liu, S. F. Parker, X. Han, S. Yang, Y. Wang, Nat. Commun., 2016, 7, 11162.
[15]	T. Li, Y. Meng, L. Yin, B. Sun, W. Zhu, J. Su, K. Wang, Appl. Catal. B, 2024, 353, 124092.
[16]	P. C. A. B. Joseph Zakzeski, Anna L. Jongerius, Bert M. Weckhuysen, Chem. Rev., 2010, 110, 3552-3599.
[17]	C. Zhang, F. Wang, Acc. Chem. Res., 2020, 53, 470-484.
[18]	Y. Li, Y. Yu, Y. Lou, S. Zeng, Y. Sun, Y. Liu, H. Yu, Angew. Chem. Int. Ed., 2023, 62, e202307116.
[19]	Q. Xia, Yi. Shao, L. Dong, X. Liu, X. Han, S. F. Parker, Y. Cheng, L. L. Daemen, A. J. Ramirez-Cuesta, S. Yang, Y. Wang, Nat. Commun., 2017, 8, 16104.
[20]	L. Dong, L.-L. Yin, Q. Xia, X. Liu, X.-Q. Gong, Y. Wang, Catal. Sci. Technol., 2018, 8, 735-745.
[21]	L. Dong, Y. Xin, X. Liu, Y. Guo, C.-W. Pao, J.-L. Chen, Y. Wang, Green Chem., 2019, 21, 3081-3090.
[22]	D. Ma, S. Lu, X. Liu, Y. Guo, Y. Wang, Chin. J. Catal., 2019, 40, 609-617.
[23]	Y. Xin, L. Dong, Y. Guo, X. Liu, Y. Hu, Y. Wang, J. Catal., 2019, 375, 202-212.
[24]	L. Li, L. Dong, X. Liu, Y. Guo, Y. Wang, Appl. Catal. B, 2020, 260, 118143.
[25]	L. Li, L. Dong, D. Li, Y. Guo, X. Liu, Y. Wang, ACS Catal., 2020, 10, 15197-15206.
[26]	H. Zhou, X. Liu, Y. Guo, Y. Wang, JACS Au, 2023, 3, 1911-1917.
[27]	M. T. A. Li Shuai, Ydna M. Questell-Santiago, Florent Héroguel, Yanding Li, Hoon Kim, Richard Meilan, Clint Chapple, John Ralph, Jeremy S. Luterbacher, Science, 2016, 354, 329-333.
[28]	S. Kim, S. C. Chmely, M. R. Nimlos, Y. J. Bomble, T. D. Foust, R. S. Paton, G. T. Beckham, J. Phys. Chem. Lett., 2011, 2, 2846-2852.
[29]	L. Shuai, J. Sitison, S. Sadula, J. Ding, M. C. Thies, B. Saha, ACS Catal., 2018, 8, 6507-6512.
[30]	X. Kong, C. Liu, Y. Fan, M. Li, R. Xiao, ACS Catal., 2023, 13, 10048-10055.
[31]	L. Dong, L. Lin, X. Han, X. Si, X. Liu, Y. Guo, F. Lu, S. Rudić, S. F. Parker, S. Yang, Y. Wang, Chem, 2019, 5, 1521-1536.
[32]	M. Cao, Y. Ma, T. Ruan, L. Li, B. Chen, X. Qiu, D. Fan, X. Ouyang, Chem. Eng. J., 2024, 485, 150020.
[33]	Z. Luo, C. Liu, A. Radu, D. F. de Waard, Y. Wang, J. T. Behaghel de Bueren, P. D. Kouris, M. D. Boot, J. Xiao, H. Zhang, R. Xiao, J. S. Luterbacher, E. J. M. Hensen, Nat. Chem. Eng., 2024, 1, 61-72.
[34]	J. J. H. B. Sattler, J. Ruiz-Martinez, E. Santillan-Jimenez, B. M. Weckhuysen, Chem. Rev., 2014, 114, 10613-10653.
[35]	S. Chen, X. Chang, G. Sun, T. Zhang, Y. Xu, Y. Wang, C. Pei, J. Gong, Chem. Soc. Rev., 2021, 50, 3315-3354.
[36]	S. Wang, B. He, R. Tian, C. Sun, R. Dai, X. Li, X. Wu, X. An, X. Xie, J. Colloid Interface Sci., 2018, 527, 339-345.
[37]	J. Lu, Y. Wang, C. Sun, T. Zhao, J. Zhao, Z. Wang, W. Liu, S. Wu, M. Shi, L. Bu, New J. Chem., 2021, 45, 8629-8638.
[38]	J. Marlowe, S. Deshpande, D. G. Vlachos, M. M. Abu-Omar, P. Christopher, J. Am. Chem. Soc., 2024, 146, 13862-13874.
[39]	J. Wu, J. Zhang, L. Wang, Z. Han, X. Hui, Y. Cao, J. Shi, S. Xu, P. He, H. Li, Chem. Eng. J., 2024, 488, 151083.
[40]	Q. Li, and D. G. Vlachos, ACS Sustainable Chem. Eng., 2021, 9, 16143-16152.
[41]	J. D. I. a. H. A. Elwin E. Harris, J. Am. Chem. Soc., 1938, 60, 1467-1470.
[42]	Y. Li, T. Akiyama, T. Yokoyama, Y. Matsumoto, Biomacromolecules, 2016, 17, 1921-1929.
[43]	F. Yan, C. Zhao, L. Yi, J. Zhang, B. Ge, T. Zhang, W. Li, Chin. J. Catal., 2017, 38, 1613-1620.
[44]	A. S. Rocha, A. M. S. Forrester, M. H. C. de la Cruz, C. T. da Silva, E. R. Lachter, Catal. Commun., 2008, 9, 1959-1965.