Electrooxidation of PET alkaline hydrolysate to formate and glycolate enabled by the synergistic interaction of Ag and NiFe-LDH

doi:10.1016/S1872-2067(25)64819-4

Abstract

Abstract:

Waste plastics present a significant threat to ecosystems and human health, necessitating efficient and cost-effective solutions for their conversion into high-value products. This study introduces a novel electrochemical reforming strategy to upgrade polyethylene terephthalate (PET) into valuable chemicals, primarily formic acid, while simultaneously generating hydrogen. A highly efficient electrocatalyst composed of nano-arrays of silver and NiFe layered double hydroxide (LDH) is synthesized via a hydrothermal and photo-precipitation process on a nickel foam substrate. This advanced catalyst achieves selective electrochemical conversion of ethylene glycol (EG) as PET hydrolysate to formate and glycolate with Faradaic efficiencies of 85% and 13% at 1.5 V vs. the reversible hydrogen electrode, with a stable and high current density. Density functional theory calculations reveal that the synergistic interaction between Ag and NiFe-LDH optimizes the adsorption and desorption of key intermediates on the catalytic sites, resulting in superior activity, selectivity, and stability for the electrochemical EG oxidation reaction. These findings highlight the potential of this catalyst for sustainable plastic waste valorization and renewable hydrogen production.

Key words: Ethylene glycol oxidation reaction, Electrocatalytic reforming, Polyethylene terephthalate, Plastic removal, Formic acid, Synergistic effect

Yi Ma, Huan Ge, Yong Zhang, Ning Jian, Jialing Tang, Zongkun Hu, Jing Yu, Jordi Arbiol, Canhuang Li, Luming Li, Andreu Cabot, Junshan Li. Electrooxidation of PET alkaline hydrolysate to formate and glycolate enabled by the synergistic interaction of Ag and NiFe-LDH[J]. Chinese Journal of Catalysis, 2026, 80: 282-292.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(25)64819-4

https://www.cjcatal.com/EN/Y2026/V80/I1/282

Figures/Tables 5

Fig. 1. Preparation and physical/chemical characterization of Ag/NiFe-LDH/NF. (a) Flow chart for the preparation of NiFe-LDH/NF and Ag/NiFe-LDH/NF. (b) XRD patterns of catalysts prepared Ag/NF, NiFe-LDH/NF and Ag/NiFe-LDH/NF. (c) Representative SEM images of Ag/NiFe-LDH/NF. (d) Representative TEM image for the Ag/NiFe-LDH/NF. (e) Corresponding HRTEM image. (f) EELS mapping of Ag, Ni, and Fe. (g) Corresponding EDS elemental mappings of Ag, Ni and Fe, respectively. (h) STEM and EDS line scan of an Ag NP.

Fig. 2. High-resolution Ni 2p (a), Fe 2p (b), and Ag 3d (c) XPS spectra. (d) Normalized XANES at the Ni K-edge for Ag/NiFe-LDH and /NiFe-LDH, with NiOOH, NiO, and Ni foil are used as references. (e) The corresponding k2-weighted spectra. (f) EXAFS spectra at the K-edge of Ag/NiFe-LDH. (g) Normalized EXAFS spectra at the Ni K-edge for Ag/NiFe-LDH and NiFe-LDH. (h,i) Experimental and fitting EAXFS spectra at the Ni K-edge of Ag/NiFe-LDH and NiFe-LDH, respectively. The insets in (h,i) correspond to WT-EXAFS of Ag/NiFe-LDH and NiFe-LDH, respectively.

Fig. 3. (a) EG yield of hydrolyzed PET under different conditions including reaction time, temperature, and mass of PET plastic powder in 1 mol L?1 KOH alkaline solution. (b) LSV curves at a scan rate of 10 mV s?1 for Ag/NiFe-LDH/NF electrode in 1 mol L?1 KOH and PET hydrolysis products. (c) LSV curves of Ag/NiFe-LDH/NF, Ag/NF, NiFe-LDH/NF, NF electrodes under PET hydrolysis product conditions. (d) Comparison of current densities of Ag/NiFe-LDH/NF, Ag/NF, NiFe-LDH/NF, and NF after 1000 cycles at 1.5 V vs. RHE. (e) Nyquist plots of four electrodes under PET hydrolysis products. (f) Corresponding double layer capacitance (Cdl) values under PET hydrolysis products in the non-Faraday capacitance current range. (g) CA test of four electrodes for 24 h, the inset shows the corresponding FA yield and FE. (h) Corresponding IC profile of the electrolyte after 24 h CA test.

Fig. 4. (a) CA Stability testing of Ag/NiFe-LDH/NF. (b) IC mapping curves of GA and FA. (c) Evolution of the GA and FA concentration with CA time. (d) FEs at each time. (e) CA test of glassy carbon electrodes loaded with Ag particles. (f) IC profiles after CA testing. (g) Reaction pathways for the oxidation of Ag/Ni-Fe LDH to FA and ethanoic acid.

Fig. 5. DFT calculations. (a) Constructed NiFe-OOH and Ag/NiFe-OOH models. (b) PDOS of these two models. (c) Charge density distribution of the Ag/NiFe-OOH. (d) Adsorption energy of EG molecules on NiFe-OOH and Ag/NiFe-OOH. (e) Gibbs free energy diagrams for EGOR to formate in the two catalysts.

References

[1]	J. M. Garcia, M. L. Robertson, Science, 2017, 358, 870-872.
[2]	A. Stubbins, K. L. Law, S. E. Muñoz, T. S. Bianchi, L. Zhu, Science, 2021, 373, 51-55.
[3]	M. MacLeod, H. P. H. Arp, M. B. Tekman, A. Jahnke, Science, 2021, 373, 61-65.
[4]	Z.-X. Yuan, Y. Gao, S.-Q. Li, J. Xuan, X.-Y. Sheng, F. Zhang, Y. Zheng, P. Chen, eScience, 2025, 5, 100375.
[5]	L. C. M. Lebreton, J. van der Zwet, J.-W. Damsteeg, B. Slat, A. Andrady, J. Reisser, Nat. Commun., 2017, 8, 15611.
[6]	L. Zhu, S. Zhao, T. B. Bittar, A. Stubbins, D. Li, J. Hazard. Mater., 2020, 383, 121065.
[7]	F. Zhang, M. Zeng, R. D. Yappert, J. Sun, Y.-H. Lee, A. M. LaPointe, B. Peters, M. M. Abu-Omar, S. L. Scott, Science, 2020, 370, 437-441.
[8]	Z. Gao, B. Ma, S. Chen, J. Tian, C. Zhao, Nat. Commun., 2022, 13, 3343.
[9]	Q. Liu, J. Shang, Z. Liu, Chin. J. Catal., 2025, 71, 54-69.
[10]	H. Su, Y. Hu, H. Feng, L. Zhu, S. Wang, ACS Sustainable Chem. Eng., 2023, 11, 578-586.
[11]	J.-J. Zhao, H.-R. Zhu, C.-J. Huang, M.-H. Yin, G.-R. Li, J. Mater. Chem. A, 2025, 13, 3236-3272.
[12]	T. Uekert, M. F. Kuehnel, D. W. Wakerley, E. Reisner, Energy Environ. Sci., 2018, 11, 2853-2857.
[13]	D. Sajwan, A. Sharma, M. Sharma, V. Krishnan, ACS Catal., 2024, 14, 4865-4926.
[14]	F. Liu, X. Gao, R. Shi, Z. Guo, E. C. M. Tse, Y. Chen, Angew. Chem. Int. Ed., 2023, 62, e202300094.
[15]	X. Liu, Z. Fang, D. Xiong, S. Gong, Y. Niu, W. Chen, Z. Chen, Nano Res., 2023, 16, 4625-4633.
[16]	J. Wang, X. Li, T. Zhang, Y. Chen, T. Wang, Y. Zhao, J. Phys. Chem. Lett., 2022, 13, 622-627.
[17]	H. Zhou, Y. Ren, Z. Li, M. Xu, Y. Wang, R. Ge, X. Kong, L. Zheng, H. Duan, Nat. Commun., 2021, 12, 4679.
[18]	Y. Jiang, J. Li, X. Guo, Y. Chen, W. Sun, C. Peng, J. Colloid Interface Sci., 2025, 685, 29-37.
[19]	J. Wang, X. Li, T. Zhang, X. Chai, M. Xu, M. Feng, C. Cai, Z. Chen, X. Qian, Y. Zhao, Chem. Sci., 2024, 15, 7596-7602.
[20]	Y. Liu, C. W. S. Yeung, E. Reisner, Energy Environ. Sci., 2025, 18, 7023-7033.
[21]	J. Li, X. Zhang, X. Liu, X. Liao, J. Huang, Y. Jiang, JACS Au, 2024, 4, 3135-3145.
[22]	K. Liu, X. Gao, C.-X. Liu, R. Shi, E. C. M. Tse, F. Liu, Y. Chen, Adv. Energy Mater., 2024, 14, 2304065.
[23]	N. F. S. Khairul Anuar, F. Huyop, G. Ur-Rehman, F. Abdullah, Y. M. Normi, M. K. Sabullah, R. Abdul Wahab, Int. J. Mol. Sci., 2022, 23, 12644.
[24]	Y. Ma, H. Ge, Y. Zhang, N. Jian, J. Yu, J. Arbiol, C. Li, Y. Zhong, L. Li, H. Kang, J. Wang, A. Cabot, J. Li, ACS Sustainable Chem. Eng., 2025, 13, 5601-5612.
[25]	Y. Ma, L. Li, J. Tang, Z. Hu, Y. Zhang, H. Ge, N. Jian, J. Zhao, A. Cabot, J. Li, J. Mater. Chem. A, 2024, 12, 33917-33925.
[26]	H. Wang, B. Jiang, T.-T. Zhao, K. Jiang, Y.-Y. Yang, J. Zhang, Z. Xie, W.-B. Cai, ACS Catal., 2017, 7, 2033-2041.
[27]	H.-Z. Ma, S.-H. He, Y. Zhang, L. Wang, Y.-N. Yi, Y.-Y. Yang, ACS Sustainable Chem. Eng., 2024, 12, 12249-12259.
[28]	X.-Y. Ma, H.-Z. Ma, S.-H. He, Y. Zhang, Y.-N. Yi, Y.-Y. Yang, Mater. Today Phys., 2023, 37, 101191.
[29]	J. Wang, X. Li, M. Wang, T. Zhang, X. Chai, J. Lu, T. Wang, Y. Zhao, D. Ma, ACS Catal., 2022, 12, 6722-6728.
[30]	F. Ma, Z. Li, R. Hu, Z. Wang, J. Wang, J. Li, Y. Nie, Z. Zheng, X. Jiang, ACS Catal., 2023, 13, 14163-14172.
[31]	T. Ren, Z. Duan, H. Wang, H. Yu, K. Deng, Z. Wang, H. Wang, L. Wang, Y. Xu, ACS Catal., 2023, 13, 10394-10404.
[32]	H. Chen, K. Wan, Y. Zhang, Y. Wang, ChemSusChem, 2021, 14, 4123-4136.
[33]	W. Ou, Y. Ye, Y. Zhang, H. Zhao, W. Du, Z. Hou, Chin. J. Catal., 2025, 71, 363-374.
[34]	J. Li, L. Li, X. Ma, X. Han, C. Xing, X. Qi, R. He, J. Arbiol, H. Pan, J. Zhao, J. Deng, Y. Zhang, Y. Yang, A. Cabot, Adv. Sci., 2023, 10, 2300841.
[35]	H. Wang, R. L. Smith, X. Qi, J. Energy Chem., 2025, 101, 535-561.
[36]	J. Li, J. Chen, L. Zhang, J. Matos, L. Wang, J. Yang, Electron, 2024, 2, e63.
[37]	J. Chen, J. Li, Z. Wei, Chin. J. Catal., 2025, 73, 79-98.
[38]	D. Si, B. Xiong, L. Chen, J. Shi, Chem Catal., 2021, 1, 941-955.
[39]	W. Kong, Z. Xing, B. Fang, Y. Cui, Z. Li, W. Zhou, Appl. Catal. B, 2022, 304, 120969.
[40]	J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett., 1996, 77, 3865-3868.
[41]	G. Kresse, J. Furthmüller, Phys. Rev. B, 1996, 54, 11169-11186.
[42]	J. F. Moulder, W. F. Stickle, P. E. Sobol, K. D. Bomben,in: Handbook of X-ray Photoelectron Spectroscopy: A Reference Book of Standard Spectra for Identification and Interpretation of XPS Data, G. E. Muilenberg eds., Perkin‐Elmer Corp., Minnesota, 1992, pp. 80-81, 84-85.
[43]	X. Liu, W. Zhang, X. Wu, Y.-R. Cho, Energy Mater. Adv., 2025, 6, 0160.
[44]	H. Tu, Y. Zhong, Z. Yang, C. Zhang, Y. Ma, Y. Zhang, N. Jian, H. Ge, J. Li, Catalysts, 2025, 15, 516.
[45]	Y. Hao, C. Qiao, S. Zhang, Y. Zhu, L. Ji, C. Cao, J. Zhang, Energy Mater. Adv., 2023, 4, 0040.
[46]	J. Li, Y. Ma, J. Yu, L. Li, H. Yang, W. Gu, J. Shi, J. Wang, Y. Zhu, ChemSusChem, 2025, 18, e202401098.
[47]	Y. Ma, L. Li, Y. Zhang, N. Jian, H. Pan, J. Deng, J. Li, J. Colloid Interface Sci., 2024, 663, 971-980.
[48]	A. Anspoks, A. Kuzmin, J. Non Cryst. Solids, 2011, 357, 2604-2610.
[49]	M. Gyu Kim, H. Sang Cho, C. Hyun Yo, J. Phys. Chem. Solids, 1998, 59, 1369-1381.
[50]	M. L. Neidig, J. Sharma, H.-C. Yeh, J. S. Martinez, S. D. Conradson, A. P. Shreve, J. Am. Chem. Soc., 2011, 133, 11837-11839.
[51]	I. Danaee, M. Jafarian, F. Forouzandeh, F. Gobal, M. Mahjani, Int. J. Hydrogen Energy, 2009, 34, 859-869.
[52]	C. Wei, S. Sun, D. Mandler, X. Wang, S.-Z. Qiao, Z. J. Xu, Chem. Soc. Rev., 2019, 48, 2518-2534.
[53]	J. Li, L. Li, J. Wang, A. Cabot, Y. Zhu, ACS Energy Lett., 2024, 9, 853-879.
[54]	H. Sun, L. Li, Y. Chen, H. Kim, X. Xu, D. Guan, Z. Hu, L. Zhang, Z. Shao, W. Jung, Appl. Catal. B, 2023, 325, 122388.
[55]	C. V. V. M. Gopi, M. Venkata-Haritha, S. Ravi, C. V. Thulasi-Varma, S.-K. Kim, H.-J. Kim, J. Mater. Chem. C, 2015, 3, 12514-12528.
[56]	X. Zhao, Z. Zhang, C. Li, L. Liu, Y. Xiao, Z. Wang, S. Li, H. S. Soo, eScience, 2025, 100431.
[57]	Z. Li, Z. Zhu, J. Wang, Y. Lin, W. Li, Y. Chen, X. Niu, X. Qi, J. Wang, J.-S. Chen, R. Wu, Adv. Funct. Mater., 2024, 34, 2410552.
[58]	L. Zhao, Z. Zhu, J. Wang, J. Zuo, H. Chen, X. Qi, X. Niu, D. J. Blackwood, J.-S. Chen, R. Wu, Adv. Mater., 2025, 2502457.
[59]	J. Li, J. Yu, Y. Zhang, C. Li, Y. Ma, H. Ge, N. Jian, L. Li, C.-Y. Zhang, J.-Y. Zhou, J. Arbiol, A. Cabot, Adv. Funct. Mater., 2025, 2501485.
[60]	N. Jian, H. Ge, Y. Ma, Y. Zhang, L. Li, J. Liu, J. Yu, C. Li, J. Li, Sci. Energy Environ., 2025, 2, 3.
[61]	M. Du, Y. Zhang, S. Kang, C. Xu, Y. Ma, L. Cai, Y. Zhu, Y. Chai, B. Qiu, Small, 2023, 19, 2303693.
[62]	R. Ciancio, R. E. Dunin-Borkowski, E. Snoeck, M. Kociak, R. Holmestad, J. Verbeeck, A. I. Kirkland, G. Kothleitner, J. Arbiol, Microsc. Microanal., 2022, 28, 2900-2902.