Efficient synthesis of flexible SCR catalysts utilizing graphene oxide as a bridging agent without calcination: Catalytic performance, mechanism and kinetics studies

doi:10.1016/S1872-2067(25)64722-X

Abstract

Abstract:

The mechanical performance of flexible catalysts remains a significant challenge for industrial applications. In this study, graphene oxide (GO) functions as both a binder and a redox mediator, serving as a crucial "bridge" between metal species and the organic foam, thereby substantially enhancing NO_x conversion efficiency. Catalytic activity tests demonstrate that the GO-modified MnCo-MS@0.05GO catalyst achieves a NO_x conversion rate exceeding 95%. The incorporation of GO strengthens the adhesion between the organic foam and metal components, increases the surface roughness of the sponge, and ensures the uniform and stable distribution of metal active sites. Additionally, GO enhances the content of effective catalytic species, improves electron transfer efficiency in the selective catalytic reduction reaction, and reduces diffusion resistance. To elucidate the NO reduction mechanism, in situ diffuse reflectance infrared Fourier transform spectroscopy and transient reaction studies were performed. The results indicate that as the reaction temperature increases, both the Eley-Rideal and Langmuir-Hinshelwood mechanisms contribute to promoting the SCR reaction rate.

Key words: Flexible materials, Selective catalytic reduction by NH₃, Graphene oxide, Redox mediator, Kinetics studies

Tingkai Xiong, Fengyu Gao, Jiajun Wen, Honghong Yi, Shunzheng Zhao, Xiaolong Tang. Efficient synthesis of flexible SCR catalysts utilizing graphene oxide as a bridging agent without calcination: Catalytic performance, mechanism and kinetics studies[J]. Chinese Journal of Catalysis, 2025, 74: 377-393.

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URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(25)64722-X

https://www.cjcatal.com/EN/Y2025/V74/I7/377

Figures/Tables 17

Scheme 1. Schematic illustration of the fabrication for the MnCo-MS@GO catalyst.

Fig. 1. NOx conversion and rate constant k (a), N2 selectivity (b), NH3 conversion (c) for MnCo-MS@0.02GO, MnCo-MS@0.05GO, MnCo-MS@0.08GO, and MnCo-MS@0.10GO. (d) Arrhenius plots of the reaction rates of catalysts at 60-120 °C. (e) NOx conversion and Rate constant k for MnCo-MS, MS@0.05GO, and MnCo-MS@0.05GO. (f) TOF value for MnCo-MS and MnCo-MS@0.05GO.

Fig. 2. Effect of SO2 or H2O on NH3-SCR performance over MnCo-MS@0.05GO catalysts: H2O tolerance test (a), SO2 tolerance test (b), H2O+SO2 tolerance test (c). (d) Stability test, NOx conversion and rate constant k (e), compression cycle testing (f) and compression yield strain (g) after 1, 3, 5 times of MnCo-MS@0.05GO catalyst utilization (After washed in water and alcohol). The feed contained 500 × 10-6 NO, 500 × 10-6 NH3, 5 vol% O2, 100 × 10-6 SO2 (when used), 10 vol% H2O (when used) and balance N2, reaction temperature 225 °C. TG (h) and DTG (i) curves of MnCo-MS@0.05GO and MnCo-MS@0.05GO after SO2.

Fig. 3. SEM images of MnCo-MS (a,d), MS@0.05GO (b,e) and MnCo-MS@0.05GO (c,f).

Fig. 4. SEM images of EDS mapping and element distribution over MnCo-MS@0.05GO catalyst (a-k) and MnCo-MS (f-l). SEM-EDS line scanning results of the MnCo-MS@0.05GO: (m) SEM image; (n) line scanning data of elemental distribution.

Fig. 5. The Raman images (a) and IR spectrum (c) of MS, GO, MS@0.05GO, and MnCo-MS@0.05GO. (b) The XRD patterns of MnCo-MS and MnCo-MS@0.05GO. The Raman Mapping of original sample (d), 1355 cm-1 (e), 1585 cm-1 (f), and 659 cm-1 (g).

Table 1 The D/G ratio of GO, MS@0.05GO and MnCo-MS@0.05GO.

Sample	Percentage of D peak	Percentage of G peak	The ratio of D/G
GO	60.44	39.56	1.53
MS@0.05GO	60.07	39.93	1.50
MnCo-MS@0.05GO	53.73	46.27	1.16

Table 2 The relative atomic contents of the MnCo-MS and MnCo-MS@0.05GO catalysts.

Sample	Surface composition (at%)				XPS date relative ratio (at%)
Sample	C	O	Mn	Co	(Mn⁴⁺+Mn³⁺)/Mn	Oα/O	Co³⁺/Co
MnCo-MS	36.8	32.6	11.6	3.6	56.4	49.8	22.0
MnCo-MS@0.05GO	39.3	44.5	9.1	2.7	77.2	65.3	59.0

Fig. 6. XPS spectra of MnCo-MS@0.05GO catalyst and MnCo-MS.

Fig. 7. H2-TPR and NH3-TPD spectra of MnCo-MS@0.05GO and MnCo-MS catalysts. (a) NH3-TPD spectra; (b) Percentage of NH3 adsorption; (c) H2-TPR spectrum; (d) Percentage of H2 consumption.

Fig. 8. Electrochemical impedance spectroscopy (a) and cyclic voltammetry (b).

Fig. 9. In-situ DRIFT spectra for the adsorption of NH3 (a) and the corresponding mapping results (b). The adsorption of NO+O2 (c) and the corresponding mapping results (d).

Fig. 10. In-situ DRIFT spectra for the pre-adsorbed NH3 and NO+O2 (a) and the corresponding mapping results (b). The pre-adsorbed NO+O2 and NH3 (c) and the corresponding mapping results (d).

Fig. 11. (a) Transient reaction taken at 150 °C upon passing NO+O2 over NH3 presorbed MnCo-MS@0.05GO. (b) Transient reaction taken at 150 °C upon passing NH3 over NO + O2 presorbed MnCo-MS@0.05GO.

Fig. 12. The reaction rate of MnCo-MS@0.05GO catalyst related to different NO concentration. (a) NOx conversion rate; (b) N2O formation rate. Reaction conditions: [NO] = [NH3] = 500 × 10?6, [O2] = 5 vol%, N2 balance, WHSV = 2500-10000 h?1.

Table 3 The steady-state kinetic parameters of MnCO-MS@0.05GO catalysts.

Sample	Temperature/°C	k_NO=k_SCR-LH+k_SCR-ER[NO_(g)]+k_NSCR			R²
Sample	Temperature/°C	k_SCR-LH	k_SCR-ER	k_NSCR	R²
MnCo-MS @0.05GO	120	5.46	0.010	0	0.999
	150	6.82	0.027	2.01	0.996
	180	7.89	0.046	6.99	0.999
	200	8.46	0.064	11.71	0.998
	220	9.60	0.078	22.03	0.995

Fig. 13. Contribution of the E-R mechanism and the L-H mechanism to the SCR reaction over MnCo-MS@0.05GO.

References

[1]	K. Guo, J. Ji, W. Song, J. Sun, C. Tang, L. Dong, Appl. Catal. B, 2021, 297, 120388.
[2]	X. Fang, Y. Liu, L. Chen, Y. Cheng, Chem. Eng. J., 2020, 399, 125798.
[3]	X. Wu, H. Meng, Y. Du, J. Liu, B. Hou, X. Xie, ACS Appl. Mater. Interfaces, 2019, 11, 32917-32927.
[4]	C. Wang, F. Gao, S. Ko, H. Liu, H. Yi, X. Tang, Chem. Eng. J., 2022, 434, 134729.
[5]	K. Zhang, N. Luo, Z. Huang, G. Zhao, F. Chu, R. Yang, X. Tang, G. Wang, F. Gao, X. Huang, Chem. Eng. J., 2023, 476, 146889.
[6]	J. Gao, C. Lu, W. Su, Z. Li, X. Li, Y. Zhao, G. Deng, K. Li, Process. Saf. Environ. Prot., 2022, 161, 658-668.
[7]	J. Xie, J. Ye, F. Pan, X. Sun, K. Ni, H. Yuan, X. Wang, N. Shu, C. Chen, Y. Zhu, Adv. Mater., 2019, 31, 1805654.
[8]	H. Guan, R. Lian, R. Li, J. Zhu, Z. Zhao, L. Liu, X. Chen, C. Jiao, S. Kuang, Adv. Funct. Mater., 2024, 34, 2313224.
[9]	D. Lin, P. Duan, W. Yang, X. Huang, Y. Zhao, C. Wang, Q. Pan, Chem. Eng. J., 2022, 430, 132817.
[10]	R. Chen, X. Fang, J. Li, Y. Zhang, Z. Liu, Chem. Eng. J., 2023, 452, 139207.
[11]	W. Song, Q. Cheng, L. Han, J. Ji, Y. Cai, W. Tan, J. Sun, C. Tang, L. Dong, Appl. Catal. B, 2024, 344, 123607.
[12]	L. Han, S. Cai, M. Gao, J.-Y. Hasegawa, P. Wang, J. Zhang, L. Shi, D. Zhang, Chem. Rev., 2019, 119, 10916-10976.
[13]	Y. Shen, T. Li, J. Yang, A. Wang, L. Wang, W. Zhan, Y. Guo, Y. Guo,, Chem. Eng. J., 2023, 473, 145275.
[14]	J. Lin, X. Hu, Y. Li, W. Shan, X. Tan, H. He, Appl. Catal. B, 2023, 331, 122705.
[15]	X. Li, Y. Niu, J. Li, M. Yang, R. Chen, D. Shao, X. Zheng, C. Zhang, Y. Qi, Chem. Eng. J., 2023, 454, 140180.
[16]	W. Zhang, X. Shi, Z. Yan, Y. Shan, Y. Zhu, Y. Yu, H. He, ACS Catal., 2021, 11, 9825-9836.
[17]	T. Xiong, F. Gao, J. Wang, J. Wen, Y. Zhou, H. Yi, S. Zhao, X. Tang, Sep. Purif. Technol., 2024, 333, 125949.
[18]	H. Chen, Z. Yu, R. Jiang, J. Huang, Y. Hou, Y. Zhang, H. Zhu, B. Wang, M. Wang, W. Tang, Nanoscale, 2021, 13, 6644-6653.
[19]	L. Shi, C. Wu, Y. Wang, Y. Dou, D. Yuan, H. Li, H. Huang, Y. Zhang, I. D. Gates, X. Sun, T. Ma, Adv. Funct. Mater., 2022, 32, 2202571.
[20]	Z. Zhao, H. Ren, D. Yang, Y. Han, J. Shi, K. An, Y. Chen, Y. Shi, W. Wang, J. Tan, X. Xin, Y. Zhang, Z. Jiang, ACS Catal., 2021, 11, 9986-9995.
[21]	S. Mou, J. Huang, J. Hou, C. Gao, J. Bai, G. Xu, P. Li, ACS Appl. Nano Mater., 2022, 5, 5326-5334.
[22]	S. Presolski, M. Pumera, Angew. Chem. Int. Ed., 2018, 57, 16713-16715.
[23]	J.-M. Jeon, T. L. Kim, Y.-S. Shim, Y. R. Choi, S. Choi, S. Lee, K. C. Kwon, S.-H. Hong, Y.-W. Kim, S. Y. Kim, M. Kim, H. W. Jang, Adv. Mater., 2017, 29, 1605929.
[24]	C.-H. Deng, J.-L. Gong, P. Zhang, G.-M. Zeng, B. Song, H.-Y. Liu, J. Colloid Interface Sci., 2017, 488, 26-38.
[25]	Z. Chen, S. Ren, X. Xing, X. Li, L. Chen, M. Wang, Fuel, 2023, 335, 126986.
[26]	X. Tang, C. Li, H. Yi, L. Wang, Q. Yu, F. Gao, X. Cui, C. Chu, J. Li, R. Zhang, Chem. Eng. J., 2018, 333, 467-476.
[27]	N. Zhang, L. Li, Y. Guo, J. He, R. Wu, L. Song, G. Zhang, J. Zhao, D. Wang, H. He, Appl. Catal. B, 2020, 270, 118860.
[28]	G. Xu, X. Guo, X. Cheng, J. Yu, B. Fang, Nanoscale, 2021, 13, 7052-7080.
[29]	L. Jiang, Q. Liu, G. Ran, M. Kong, S. Ren, J. Yang, J. Li, Chem. Eng. J., 2019, 370, 810-821.
[30]	A. Y. Molokova, R. K. Abasabadi, E. Borfecchia, O. Mathon, S. Bordiga, F. Wen, G. Berlier, T. V. W. Janssens, K. A. Lomachenko, Chem. Sci., 2023, 14, 11521-11531.
[31]	J. D. Bjerregaard, M. Votsmeier, H. Grönbeck, J. Catal., 2023, 417, 497-506.
[32]	T. Zhao, X. Huang, R. Cui, G. Zhang, Z. Tang, Nanoscale, 2023, 15, 12540-12557.
[33]	G. Huang, J. Yang, C. Lv, D. Li, D. Fang, J. Environ. Chem. Eng., 2023, 11, 110966.
[34]	D. Y. Kornilov, S. P. Gubin, Russ. J. Inorg. Chem., 2020, 65, 1965-1976.
[35]	Y. Zhu, Z. Zhang, J. Build. Eng., 2021, 44, 103302.
[36]	L. Sun, K. Li, Z. Zhang, X. Hu, H. Tian, Y. Zhang, X. Yang, Catal. Sci. Technol., 2019, 9, 1602-1608.
[37]	W. Liu, Y. Gao, Y. Yang, Q. Zou, G. Yang, Z. Zhang, H. Li, Y. Miao, H. Li, Y. Huo, ChemCatChem, 2018, 10, 2394-2400.
[38]	J.-B. Wu, M.-L. Lin, X. Cong, H.-N. Liu, P.-H. Tan, Chem. Soc. Rev., 2018, 47, 1822-1873.
[39]	S. Wan, Y. Chen, Y. Wang, G. Li, G. Wang, L. Liu, J. Zhang, Y. Liu, Z. Xu, A. P. Tomsia, L. Jiang, Q. Cheng, Matter, 2019, 1, 389-401.
[40]	J. Liu, Y. Liu, H.-B. Zhang, Y. Dai, Z. Liu, Z.-Z. Yu, Carbon, 2018, 132, 95-103.
[41]	N. Aljammal, C. Jabbour, S. Chaemchuen, T. Juzsakova, F. Verpoort, Catalysts, 2019, 9, 512.
[42]	N. Al Amery, H. R. Abid, S. Al-Saadi, S. Wang, S. Liu, Mater. Today Chem., 2020, 17, 100343.
[43]	W. Liu, M. Li, H. Jiang, X. Zhang, J. Qiao, J. Nanopart. Res., 2019, 21, 36.
[44]	C. Chen, X. Zhu, B. Chen, Environ. Sci. Technol., 2019, 53, 1509-1517.
[45]	X. Zhu, G. Zhou, G. He, L. Ma, B. Xu, F. Sun, Surf. Interfaces, 2023, 36, 102575.
[46]	T. Bakhiia, A. Y. Romanchuk, K. I. Maslakov, A. A. Averin, S. N. Kalmykov, Energies, 2022, 15, 7371.
[47]	C. Wang, X. Tang, H. Yi, F. Gao, S. Ni, R. Zhang, Y. Shi, Colloids Surf. A, 2021, 612, 126007.
[48]	J. O. Olowoyo, M. Kumar, B. Singh, V. O. Oninla, J. O. Babalola, H. Valdés, A. V. Vorontsov, U. Kumar, Carbon, 2019, 147, 385-397.
[49]	I. Shown, H.-C. Hsu, Y.-C. Chang, C.-H. Lin, P. K. Roy, A. Ganguly, C.-H. Wang, J.-K. Chang, C.-I. Wu, L.-C. Chen, K.-H. Chen, Nano Lett., 2014, 14, 6097-6103.
[50]	X. Tang, C. Wang, F. Gao, R. Zhang, Y. Shi, H. Yi, J. Colloid Interface Sci., 2021, 603, 291-306.
[51]	T. Zhang, T. Shi, Y. Wang, Y. Hao, Y. Gao, H. Li, L. Jia, F. Liu, S. Zeng, J. Catal., 2024, 429, 115260.
[52]	X. Xu, X. Liu, L. Ma, N. Liang, S. Yang, H. Liu, J. Sun, F. Huang, C. Sun, L. Dong, ACS Catal., 2024, 14, 3028-3040.
[53]	F. Liu, J. Li, H. Y. Sohn, C. Chen, J. Yang, X. Liu, Y. Lan, W. Zhang, Q. Wang, L. Liu, Fuel, 2023, 350, 128806.
[54]	Y. Wu, Y. Li, J. He, X. Fang, P. Hong, M. Nie, W. Yang, C. Xie, Z. Wu, K. Zhang, L. Kong, J. Liu, J. Colloid Interface Sci., 2020, 562, 1-11.
[55]	A. Ambrosi, C. K. Chua, N. M. Latiff, A. H. Loo, C. H. A. Wong, A. Y. S. Eng, A. Bonanni, M. Pumera, Chem. Soc. Rev., 2016, 45, 2458-2493.
[56]	H. Liu, F. Gao, S. Ko, N. Luo, X. Tang, H. Yi, Y. Zhou, Appl. Catal. B, 2023, 330, 122651.
[57]	S. Yang, C. Wang, J. Li, N. Yan, L. Ma, H. Chang, Appl. Catal. B, 2011, 110, 71-80.
[58]	L.-Y. Lin, Y.-C. Wang, Z.-L. Liu, Chem. Eng. J., 2024, 484, 149637.
[59]	S. Yang, Y. Fu, Y. Liao, S. Xiong, Z. Qu, N. Yan, J. Li, Catal. Sci. Technol., 2014, 4, 224-232.
[60]	S. Yang, S. Xiong, Y. Liao, X. Xiao, F. Qi, Y. Peng, Y. Fu, W. Shan, J. Li, Environ. Sci. Technol., 2014, 48, 10354-10362.