Preparation and catalytic performance of Ru-Co/SiC catalysts for the synthesis of heavy hydrocarbons from syngas by Fischer-Tropsch reaction

doi:10.11949/0438-1157.20210260

Abstract

Abstract:

Fischer-Tropsch (F-T) synthesis is an important way to produce clean fuels and other chemicals from syngas. The traditional F-T synthesis follows Anderson-Schulz-Flory distribution, except for methane and heavy hydrocarbons, where its selectivity has no limit. Therefore, maximizing the yields of heavy hydrocarbons to further obtain high quality diesel and aviation kerosene by hydrocracking and hydroisomerization has been the research focus for F-T synthesis. The present work compared the effects of different supports (SiO₂, Al₂O₃ and SiC) on the catalytic performance of cobalt-based catalysts for F-T synthesis, in which SiC showed the highest activity (83.5%) and C₅₊ selectivity (80.3%). Compared to impregnation method, introducing Ru promoter by in-situ reduction method is more effective, with C₅₊ selectivity being further increased to 90.1%. Ru promoter could improve the C₅₊ selectivity while maintaining a high catalytic performance of Co/SiC catalyst. The characterization (XRD, H₂-TPR, XPS, H₂-chemisorption and TEM) results demonstrated the interaction between Ru and Co, thereby enhancing the reducibility and dispersion of active components and improved the selectivity for heavy hydrocarbons of Co/SiC catalyst.

Key words: Fischer-Tropsch synthesis, cobalt catalyst, in-situ reduction preparation, heavy hydrocarbons

摘要：

费托合成是以合成气生产清洁燃料和其他化学品的重要途径。传统费托合成产物遵循A-S-F分布，只有甲烷和重质烃的选择性没有极限值。因此，费托合成研究以最大程度地合成重质烃，提高合成产物中重质烃的选择性为目标。基于此，首先详细探究了Al₂O₃、SiO₂和SiC载体对费托反应性能的影响。结果表明 Co/SiC催化剂具有最高的CO转化率（83.5%）和C₅₊选择性（80.3%）。与浸渍法相比，原位还原法更为有效地引入Ru到Co/SiC催化剂，将C₅₊选择性提高至90.1%。Ru助剂能在保持较高催化活性不变的前提下，有效提高Co/SiC催化剂C₅₊选择性。催化剂表征（XRD、H₂-TPR、XPS、H₂-化学吸附和TEM）结果表明，Ru能与Co发生相互作用，提高了催化剂的可还原性和活性组分的分散性，进而改善了Co/SiC催化剂重质烃的选择性。

关键词: 费托合成, 钴基催化剂, 原位还原, 重质烃

CLC Number:

TQ 546.4

TAN Khangwei, XIONG Wenting, FU Jile, CHEN Binghui. Preparation and catalytic performance of Ru-Co/SiC catalysts for the synthesis of heavy hydrocarbons from syngas by Fischer-Tropsch reaction[J]. CIESC Journal, 2021, 72(7): 3648-3657.

陈康伟, 熊文婷, 符继乐, 陈秉辉. 合成气费托合成制重质烃Ru-Co/SiC催化剂的制备及性能[J]. 化工学报, 2021, 72(7): 3648-3657.

Figures/Tables 15

Fig.1 Preparation process of cobalt based catalyst

Fig.2 The experimental set-up of F-T synthesis

Table 1 Effect of supports on the catalytic performance of Co-based catalysts

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co/SiC	83.5	9.0	9.7	80.3	1.0
Co/SiO₂	71.9	9.2	11.2	78.5	1.1
Co/Al₂O₃	75.4	15.4	14.0	69.1	1.5

Table 1 Effect of supports on the catalytic performance of Co-based catalysts

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co/SiC	83.5	9.0	9.7	80.3	1.0
Co/SiO₂	71.9	9.2	11.2	78.5	1.1
Co/Al₂O₃	75.4	15.4	14.0	69.1	1.5

Table 2 Effect of cobalt sources on the catalytic performance of the Co/SiC catalysts

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co(N)/SiC	83.5	9.0	9.7	80.3	1.0
Co(A)/SiC	55.6	18.9	20.9	57.7	2.5

Table 2 Effect of cobalt sources on the catalytic performance of the Co/SiC catalysts

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co(N)/SiC	83.5	9.0	9.7	80.3	1.0
Co(A)/SiC	55.6	18.9	20.9	57.7	2.5

Table 3 The effect of Ru addition on the catalytic performance of Co-based catalysts for F-T synthesis

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co/SiC	83.5	9.0	9.8	80.3	1.0
Ru/Co/SiC	82.3	5.2	6.5	86.6	1.7
Ru-Co/SiC	83.1	4.6	3.7	90.1	1.5

Table 3 The effect of Ru addition on the catalytic performance of Co-based catalysts for F-T synthesis

Catalyst	X_CO/%	$S C H 4$ /%	$S C 2 — C 4$ /%	$S C 5 +$ /%	$S C O 2$ /%
Co/SiC	83.5	9.0	9.8	80.3	1.0
Ru/Co/SiC	82.3	5.2	6.5	86.6	1.7
Ru-Co/SiC	83.1	4.6	3.7	90.1	1.5

Fig.3 XRD patterns of Co/SiC, Ru/Co/SiC and Ru-Co/SiC catalysts

Table 4 The crystallite sizes of Co species in Co/SiC， Ru/Co/SiC and Ru-Co/SiC catalysts

Catalyst	Particle size of Co₃O₄/nm	Particle size of Co/nm
Co/SiC	41.9	23.1
Ru/Co/SiC	30.1	19.2
Ru-Co/SiC	16.5	8.5

Table 5 The surface area and pore structure data of Co/SiC， Ru/Co/SiC and Ru-Co/SiC catalysts

Catalyst	BET/(m²/g)	Pore volume/(cm³/g)	Pore diameter/nm
SiC	23.9	0.15	25.0
Co/SiC	21.8	0.12	22.0
Ru/Co/SiC	24.5	0.19	30.4
Ru-Co/SiC	55.1	0.25	17.9

Fig.4 H2-TPR profiles of fresh Co/SiC, Ru/Co/SiC and Ru-Co/SiC catalysts

Fig.5 EDS spectra of Co/SiC, Ru/Co/SiC, Ru-Co/SiC catalysts

Fig.6 TEM images of Co/SiC, Ru/Co/SiC and Ru-Co/SiC catalysts

Table 6 The element content of Co/SiC， Ru/Co/SiC and Ru-Co/SiC catalysts

Catalyst	Element content/%
Catalyst	Co	Ru
Co/SiC	21.7	—
Ru/Co/SiC	20.8	0.65
Ru-Co/SiC	20.2	0.71

Table 7 The data of metal dispersion and metallic surface area for Co/SiC， Ru-Co/SiC and Ru/Co/SiC catalysts

Catalyst	H₂-chemisorption
Catalyst	Metal dispersion /%	Metallic surface area /(m²/g)
Co/SiC	0.35	0.47
Ru/Co/SiC	0.38	0.51
Ru-Co/SiC	0.42	0.57

Fig.7 XPS spectra of Co/SiC, Ru-Co/SiC and Ru/Co/SiC catalysts

Table 8 XPS analysis results of Co/SiC， Ru/Co/SiC and Ru-Co/SiC catalysts

Catalyst	BE/eV		Intensity ratio
Catalyst	Co 2p3/2	Ru 3p1/2	I_C_o/I_Si	I_Ru/I_Si	$I C o 3 + / I C o 2 +$	$I R u 0 / I R u 4 +$
Co/SiC	780.9	—	0.4	—	1.3	—
Ru/Co/SiC	780.5	463.8	0.6	0.1	1.9	1.2
Ru-Co/SiC	781.1	464.1	1.8	0.1	2.1	1.3

Table 8 XPS analysis results of Co/SiC， Ru/Co/SiC and Ru-Co/SiC catalysts

Catalyst	BE/eV		Intensity ratio
Catalyst	Co 2p3/2	Ru 3p1/2	I_C_o/I_Si	I_Ru/I_Si	$I C o 3 + / I C o 2 +$	$I R u 0 / I R u 4 +$
Co/SiC	780.9	—	0.4	—	1.3	—
Ru/Co/SiC	780.5	463.8	0.6	0.1	1.9	1.2
Ru-Co/SiC	781.1	464.1	1.8	0.1	2.1	1.3

References 31

1	Dry M E. The Fischer-Tropsch process: 1950—2000[J]. Catalysis Today, 2002, 71(3/4): 227-241.
2	Khodakov A Y, Chu W, Fongarland P. Advances in the development of novel cobalt Fischer-Tropsch catalysts for synthesis of long-chain hydrocarbons and clean fuels[J]. Chem. Rev., 2007, 107(5): 1692-1744.
3	Fu T, Li Z. Review of recent development in Co-based catalysts supported on carbon materials for Fischer-Tropsch synthesis[J]. Chemical Engineering Science, 2015, 135: 3-20.
4	Storsæter S, Tøtdal B, Walmsley J C, et al. Characterization of alumina-, silica-, and titania-supported cobalt Fischer-Tropsch catalysts[J]. Journal of Catalysis, 2005, 236: 139-52.
5	Zhang Y, Qing M, Wang H, et al. Comprehensive understanding of SiO₂-promoted Fe Fischer-Tropsch synthesis catalysts: Fe-SiO₂ interaction and beyond[J]. Catalysis Today, 2021, 368: 96-105.
6	Liu X D, Wang J T, Hu Z Q, et al. Structure and properties of Fe-based nanocrystalline alloys containing a small amount of transition elements[J]. Materials Science and Engineering: A, 1993, 169: L17-L19.
7	Jacobs G, Chaney J A, Patterson P M, et al. Fischer-Tropsch synthesis: study of the promotion of Re on the reduction property of Co/Al₂O₃ catalysts by in situ EXAFS/XANES of Co K and Re LIII edges and XPS[J]. Applied Catalysis A: General, 2004, 264(2): 203-212.
8	Shimura K, Miyazawa T, Hanaoka T, et al. Fischer-Tropsch synthesis over TiO₂ supported cobalt catalyst: effect of TiO₂ crystal phase and metal ion loading[J]. Applied Catalysis A: General, 2013, 460/461: 8-14.
9	Díaz J A, Calvo-Serrano M, de la Osa A R, et al. Β-silicon carbide as a catalyst support in the Fischer-Tropsch synthesis: influence of the modification of the support by a pore agent and acidic treatment[J]. Applied Catalysis A: General, 2014, 475: 82-89.
10	Petersen E M, Rao R G, Vance B C, et al. SiO₂/SiC supports with tailored thermal conductivity to reveal the effect of surface temperature on Ru-catalyzed CO₂ methanation[J]. Applied Catalysis B: Environmental, 2021, 286: 119904.
11	Zhu X W, Lu X J, Liu X Y, et al. Heat transfer study with and without Fischer-Tropsch reaction in a fixed bed reactor with TiO₂, SiO₂, and SiC supported cobalt catalysts[J]. Chemical Engineering Journal, 2014, 247: 75-84.
12	Lacroix M, Dreibine L, de Tymowski B, et al. Silicon carbide foam composite containing cobalt as a highly selective and re-usable Fischer-Tropsch synthesis catalyst[J]. Applied Catalysis A: General, 2011, 397(1/2): 62-72.
13	Jacobs G, Das T K, Zhang Y Q, et al. Fischer-Tropsch synthesis: support, loading, and promoter effects on the reducibility of cobalt catalysts[J]. Applied Catalysis A: General, 2002, 233(1/2): 263-281.
14	Ma W P, Jacobs G, Keogh R A, et al. Fischer-Tropsch synthesis: effect of Pd, Pt, Re, and Ru noble metal promoters on the activity and selectivity of a 25%Co/Al₂O₃ catalyst[J]. Applied Catalysis A: General, 2012, 437/438: 1-9.
15	Noh Y S, Lee K Y, Moon D J. Studies on the Fischer-Tropsch synthesis over RuCo/SiC-Al₂O₃ structured catalyst[J]. Catalysis Today, 2020, 348: 157-165.
16	Rezaei B, Havakeshian E, Ensafi A A. Decoration of nanoporous stainless steel with nanostructured gold via galvanic replacement reaction and its application for electrochemical determination of dopamine[J]. Sensors and Actuators B: Chemical, 2015, 213: 484-492.
17	Song H Q, Zhao Q Z, Zhou X, et al. Selection of highly active and stable Co supported SiC catalyst for Fischer-Tropsch synthesis: effect of the preparation method[J]. Fuel, 2018, 229: 144-150.
18	Khodakov A Y. Enhancing cobalt dispersion in supported Fischer-Tropsch catalysts via controlled decomposition of cobalt precursors[J]. Brazilian Journal of Physics, 2009, 39(1a): 171-175.
19	Gholami Z, Tišler Z, Rubáš V. Recent advances in Fischer-Tropsch synthesis using cobalt-based catalysts: a review on supports, promoters, and reactors[J]. Catalysis Reviews, 2020, doi.org/10.1080/01614940.2020.1762367.
20	Zhang Q H, Cheng K, Kang J C, et al. Fischer-Tropsch catalysts for the production of hydrocarbon fuels with high selectivity[J]. ChemSusChem, 2014, 7(5): 1251-1264.
21	Koo H M, Lee B S, Park M J, et al. Fischer-Tropsch synthesis on cobalt/Al₂O₃-modified SiC catalysts: effect of cobalt-alumina interactions[J]. Catalysis Science & Technology, 2014, 4(2): 343-351.
22	Sari A. Investigation of the supercritical conditions for Fischer-Tropsch reaction over an industrial Co-Ru/γ-Al₂O₃ catalyst[J]. Chemical Engineering Journal, 2014, 244: 317-326.
23	Song S H, Lee S B, Bae J W, et al. A comparison with that of Ru-Co/SiO₂ catalysts[J]. Catalysis Communications, 2008, 9: 2282.
24	Park J Y, Lee Y J, Karandikar P R, et al. Ru promoted cobalt catalyst on γ-Al₂O₃ support: influence of pre-synthesized nanoparticles on Fischer-Tropsch reaction[J]. Journal of Molecular Catalysis A: Chemical, 2011, 344(1/2): 153-160.
25	Parnian M J, Khodadadi A A, Taheri Najafabadi A, et al. Preferential chemical vapor deposition of ruthenium on cobalt with highly enhanced activity and selectivity for Fischer-Tropsch synthesis[J]. Applied Catalysis A: General, 2014, 470: 221-231.
26	Jabbour K, El Hassan N, Casale S, et al. Promotional effect of Ru on the activity and stability of Co/SBA-15 catalysts in dry reforming of methane[J]. International Journal of Hydrogen Energy, 2014, 39(15): 7780-7787.
27	Kungurova O A, Khassin A A, Cherepanova S V, et al. Δ-Alumina supported cobalt catalysts promoted by ruthenium for Fischer-Tropsch synthesis[J]. Applied Catalysis A: General, 2017, 539: 48-58.
28	Gorimbo J, Muvhiiwa R, Llane E, et al. Cobalt catalyst reduction thermodynamics in Fischer-Tropsch: an attainable region approach[J]. Reactions, 2020, 1(2): 115-129.
29	Parnian M J, Taheri Najafabadi A, Mortazavi Y, et al. Ru promoted cobalt catalyst on γ-Al₂O₃: influence of different catalyst preparation method and Ru loadings on Fischer-Tropsch reaction and kinetics[J]. Applied Surface Science, 2014, 313: 183-195.
30	Kungurova O A, Shtertser N V, Chermashentseva G K, et al. Ruthenium promoted cobalt-alumina catalysts for the synthesis of high-molecular-weight solid hydrocarbons from CO and hydrogen[J]. Catalysis in Industry, 2017, 9(1): 23-30.
31	Dehghan R, Hansen T W, Wagner J B, et al. In-situ reduction of promoted cobalt oxide supported on alumina by environmental transmission electron microscopy[J]. Catalysis Letters, 2011, 141(6): 754-761.

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