Relationship between palladium nuclearity and catalytic activity and selectivity in acetylene semi-hydrogenation

doi:10.1016/S1872-2067(26)64982-0

Abstract

Abstract:

Optimizing the noble metal utilization and stability in catalysts for acetylene semi-hydrogenation reaction while maintaining high activity and ethylene selectivity is crucial for catalyst implementation on the industrial scale. Here we tune the reduction temperature of a single-atom Pd catalyst supported on N-doped carbon to regulate the populations of Pd species and quantify their contributions to acetylene semi-hydrogenation. X-ray absorption near-edge structure linear-combination fitting and extended X-ray absorption fine structure (EXAFS) wavelet transform analysis, complemented by in-situ EXAFS under reaction conditions, resolves the evolution from isolated Pd atoms (Pd₁) to 2-3 atom ensembles (Pd_2/3), clusters, and nanoparticles. Reduction at 200 °C generates around 9% Pd_2/3 within a Pd₁ population. Kinetic deconvolution at low conversion shows that Pd_2/3 are 10 times more active than Pd₁ while maintaining high ethylene selectivity and low ethane formation; in-situ EXAFS confirms the stability of these ensembles. Increasing the reduction temperature to 400 °C eliminates Pd_2/3 in favor of Pd clusters whose per-site turnover frequency is around 25-30 times higher than that of Pd₁ but with a slight decrease in ethylene selectivity. After reduction at 600 °C, the catalyst contains 34 ± 6% Pd nanoparticles and 17 ± 6% clusters, delivering high conversion yet reducing ethylene selectivity to ’55% and increasing ethane production, consistent with over-hydrogenation on larger Pd entities. These results establish a quantitative link between Pd nuclearity and per-site kinetics.

Key words: Heterogeneous catalysis, Acetylene semi-hydrogenation, Pd single atom catalyst, Pd ensembles, Pd cluster, Structure-activity relationship

Polina Lavrik, Jurjen Cazemier, Mohamed N. Hedhili, Sudheesh K. Veeranmaril, Abdallah Nassereddine, Antonio Aguilar-Tapia, Marina Chernova, Jean-Louis Hazemann, Alla Dikhtiarenko, Javier Ruiz-Martínez. Relationship between palladium nuclearity and catalytic activity and selectivity in acetylene semi-hydrogenation[J]. Chinese Journal of Catalysis, 2026, 85: 384-393.

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URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(26)64982-0

https://www.cjcatal.com/EN/Y2026/V85/I6/384

Figures/Tables 7

Fig. 1. Characterization of Pd/CN. XRD pattern (a) and PDF spectra (b) of Pd/CN and simulated Pd-Pd and N-doped carbon. HAADF-STEM micro-graphs in low magnification (c) and atomically resolved (d). XPS signal of Pd 3d peaks and their deconvolution (e). Pd K-edge XANES (f) and FT EXAFS (g) spectra of Pd foil, PdN4, PdO references and Pd/CN. First derivative of XANES spectra (h).

Table 1 Element distribution in Pd/CN, Pd/CN-200, Pd/CN-400, and Pd/CN-600 calculated from XPS data.

Catalyst	C, at%	N, at%	Pd, at%	O, at%	C/N ratio
Pd/CN	52.7	45.5	0.2	1.6	1.16
Pd/CN-200	52.5	45.8	0.2	1.5	1.15
Pd/CN-400	52.3	46.3	0.2	1.2	1.13
Pd/CN-600	68.9	28.2	0.8	2.1	2.42

Fig. 2. Catalytic performance in acetylene hydrogenation reaction of Pd/CN, Pd/CN-200, Pd/CN-400, and Pd/CN-600 (a) and their selectivity to ethylene (b). HAADF-STEM images of Pd/CN-200 (c), Pd/CN-400 (d), and Pd/CN-600 (e) in low magnification and atomically resolved (in the upper right corner). The yellow circles are highlighting Pd particles.

Table 2 Detected species distribution for C, N and Pd in Pd/CN, Pd/CN-200, Pd/CN-400, and Pd/CN-600 calculated from XPS data.

Catalyst		Pd/CN	Pd/CN-200	Pd/CN-400	Pd/CN-600
C species, %	C=C/C-C	22	28	23	68
	C-N/C-O	19	19	18	19
	NC=N/C=O	57	51	57	6
	O-C=O	—	—	—	3
	Shake-up satellites	2	2	2	4
N species, %	C-N=C	64	64	63	55
	N-(C)₃	19	19	20	20
	C-N-H	11	11	11	18
	N*	—	—	—	3
	Shake-up satellites	6	6	6	4
Pd species, %	Pd²⁺	100	100	100	94
Pd species, %	Pd⁰	—	—	—	6

Fig. 3. XANES spectra of Pd/CN, Pd/CN-200, Pd/CN-400, Pd/CN-600, and Pd foil reference (a). In order to prevent the oxidation on air, spectra of Pd/CN-200, Pd/CN-400 and Pd/CN-600 were measured in-situ at room temperature after reduction of Pd/CN. Composition of Pd/CN, Pd/CN-200, Pd/CN-400 and Pd/CN-600 (b) summarized from the LCF (Fig. S8) of mentioned samples with measured Pd/CN as a Pd single atom reference, simulated Pd2/3/CN, simulated Pdclusters/CN, and Pd foil as metallic Pd reference. Wavelet transform graphs for Pd/CN (c), Pd/CN-200 (d), Pd/CN-400 (e), and Pd/CN-600 (f) catalysts.

Fig. 4. In-situ FT EXAFS measured under reaction conditions for Pd/CN-200 (a), Pd/CN-400 (b), and Pd/CN-600 (c). Pd/CN represents the initial state for all the catalysts; subsequent spectra were acquired after catalyst reduction. The reaction gases were introduced into the reactor and the catalysts were heated up to 85 and 135 °C with the ramp of 10 °C/min at which temperatures the spectra under the reaction conditions were obtained.

Table 3 TOF results for Pd/CN, Pd/CN-200, and Pd/CN-400 catalysts at 75 and 100 °C; calculated TOF of individual Pd1/CN, Pd2/3/CN, and Pdclusters/CN at the same temperatures if they would be the only types of species present in the catalyst in the same amount of moles.

Temperature, °C	TOF, h^-1			Estimated TOF of individual species, h^-1
Temperature, °C	Pd/CN	Pd/CN-200	Pd/CN-400	Pd₁/CN	Pd_2/3/CN	Pd_clusters/CN
75	3.2	4.9	11.4	3.2	21.9	77.4
100	6.9	12.6	29.3	6.9	70.5	210.7

References

[1]	Y. Liu J,. Zhao J,. Feng Y,. He Y,. Du D,. Li J. Catal., 2018, 359, 251-260.
[2]	A. Borodziński, G. C. Bond, Catal. Rev. Sci. Eng., 2006, 48, 91-144.
[3]	A. Borodziński, G. C. Bond, Catal. Rev. Sci. Eng., 2008, 50, 379-469.
[4]	Á. Molnár, A. Sárkány, M. Varga, J. Mol. Catal. A, 2001, 173, 185-221.
[5]	M. Armbrüster, K. Kovnir, M. Behrens, D. Teschner, Y. Grin, R. Schlögl, J. Am. Chem. Soc., 2010, 132, 14745-14747.
[6]	X. Liu Y,. Li J. W., Lee C.-Y., Hong C.-Y., Mou B. W. L. Jang, Appl. Catal. A, 2012, 439-440, 8-14.
[7]	G.-X. Pei, X.-Y. Liu, A. Wang, A. F. Lee, M. A. Isaacs, L. Li, X. Pan, X. Yang, X. Wang, Z. Tai, K. Wilson, T. Zhang, ACS Catal., 2015, 5, 3717-3725.
[8]	Z. Yuan, A. Kumar, D. Zhou, J. Feng, B. Liu, X. Sun, J. Catal., 2022, 414, 374-384.
[9]	A. Sandell, A. Beutler, A. Jaworowski, M. Wiklund, K. Heister, R. Nyholm, J. N. Andersen, Surf. Sci., 1998, 415, 411-422.
[10]	A. Borodziński, Catal. Lett., 1999, 63, 35-42.
[11]	A. M. Doyle, S. K. Shaikhutdinov S. D., Jackson H.-J. Freund, Angew. Chem. Int. Ed., 2003, 42, 5240-5243.
[12]	Y. Xiong, W. Sun, P. Xin, W. Chen, X. Zheng, W. Yan, L. Zheng, J. Dong, J. Zhang, D. Wang, Y. Li, Adv. Mater., 2020, 32, 2000896.
[13]	L. Liu A. Corma, Chem. Rev., 2018, 118, 4981-5079.
[14]	S. K. Kaiser, Z. Chen D,. Faust Akl S,. Mitchell J. Pérez-Ramírez, Chem. Rev., 2020, 120, 11703-11809.
[15]	W. Li Z,. Guo J,. Yang Y,. Li X,. Sun H,. He S,. Li J. Zhang, Electrochem. Energy Rev., 2022, 5, 9.
[16]	J. Fang, Q. Chen, Z. Li, J. Mao, Y. Li, Chem. Commun., 2023, 59, 2854-2868.
[17]	S. Zhou, L. Shang, Y. Zhao, R. Shi, G. I. N. Waterhouse, Y.-C. Huang, L. Zheng, T. Zhang, Adv. Mater., 2019, 31, 1900509.
[18]	Y. Guo Y,. Huang B,. Zeng B,. Han M,. Akri M,. Shi Y,. Zhao Q,. Li Y,. Su L,. Li Q,. Jiang Y.-T., Cui L,. Li R,. Li B,. Qiao T. Zhang, Nat. Commun., 2022, 13, 2648.
[19]	Y. Guo Y,. Li X,. Du L,. Li Q,. Jiang B. Qiao, Nano Res., 2022, 15, 10037-10043.
[20]	X. Li S,. Mitchell Y,. Fang J,. Li J,. Perez-Ramirez J. Lu, Nat. Rev. Chem., 2023, 7, 754-767.
[21]	E. Vorobyeva, E. Fako, Z. Chen, S. M. Collins, D. Johnstone, P. A. Midgley, R. Hauert, O. V. Safonova, G. Vilé, N. López, S. Mitchell, J. Pérez-Ramírez, Angew. Chem. Int. Ed., 2019, 58, 8724-8729.
[22]	R. Li Y,. Yue X,. Chen R,. Chang J,. Zhang B,. Zhao J,. Zhang D,. Cai Y,. Zhu D,. Han J,. Zhao X. Li, Nano Res., 2023, 16, 6167-6177.
[23]	I. Cabria, M. J. López, S. Fraile, J. A. Alonso, J. Phys. Chem. C, 2012, 116, 21179-21189.
[24]	S. M. Hosseini, M. Ghiaci H. Farrokhpour, Struct. Chem., 2021, 32, 2087-2097.
[25]	Y. Zhao, M. Zhu, L. Kang, Catal. Lett., 2018, 148, 2992-3002.
[26]	P. Juhás, T. Davis, C. L. Farrow, S. J. L. Billinge, J. Appl. Crystallogr., 2013, 46, 560-566.
[27]	O. Proux, V. Nassif, A. Prat, O. Ulrich, E. Lahera, X. Biquard, J.-J. Menthonnex, J.-L. Hazemann, J. Synchrotron Radiat., 2006, 13, 59-68.
[28]	A. Aguilar-Tapia, S. Ould-Chikh, E. Lahera, A. Prat, W. Delnet, O. Proux, I. Kieffer, J.-M. Basset, K. Takanabe, J.-L. Hazemann, Rev. Sci. Instrum., 2018, 89, 035109.
[29]	B. Ravel, M. Newville, J. Synchrotron Radiat., 2005, 12, 537-541.
[30]	J. Zheng, S. Zhou, S. Gu, B. Xu, Y. Yan, J. Electrochem. Soc., 2016, 163, F499-F506.
[31]	X. Wang, K. Maeda, A. Thomas, K. Takanabe, G. Xin, J. M. Carlsson, K. Domen, M. Antonietti, Nat. Mater., 2009, 8, 76-80.
[32]	S. C. Yan, Z. S. Li, Z. G. Zou, Langmuir, 2009, 25, 10397-10401.
[33]	P. D. Nellist, E. C. Cosgriff G,. Behan A. I. Kirkland, Microsc. Microanal., 2008, 14, 82-88.
[34]	J. P. Mathew, M. Srinivasan, Eur. Polym. J., 1995, 31, 835-839.
[35]	A. L. Thomann, P. Brault J. P., Rozenbaum C,. Andreazza-Vignolle P,. Andreazza H,. Estrade-Szwarckopf B,. Rousseau D,. Babonneau G. Blondiaux, J. Phys. D: Appl. Phys., 1997, 30, 3197-3202.
[36]	N. Hellgren, R. T. Haasch, S. Schmidt, L. Hultman, I. Petrov, Carbon, 2016, 108, 242-252.
[37]	E. G. Ciapina, M. L. dos Santos, R. M. I. S. Santos, J. Palombarini, O. P. Almeida Jr, J. C. C. de Castro Santana, D. A. Modesto, A. J. C. Lanfredi, S. F. Santos, J. Alloys Compd., 2021, 881, 160628.
[38]	J. Finzel, K. M. Sanroman Gutierrez, A. S. Hoffman, J. Resasco, P. Christopher, S. R. Bare, ACS Catal., 2023, 13, 6462-6473.
[39]	C. G. P. M,. Bernardo J. A. N. F. Gomes, J. Mol. Struct. THEOCHEM, 2001, 542, 263-271.
[40]	J. Prinz, C. A. Pignedoli, Q. S. Stöckl, M. Armbrüster, H. Brune, O. Gröning, R. Widmer, D. Passerone, J. Am. Chem. Soc., 2014, 136, 11792-11798.