Enhanced Fe(III)/Fe(II) cycle in heterogeneous photocatalysis-self-Fenton system for organic pollutants degradation

doi:10.1016/S1872-2067(26)65034-6

Abstract

Abstract:

Heterogeneous photocatalysis-self-Fenton systems have emerged as a promising method for wastewater treatment. However, their reaction efficiency is often severely limited by the sluggish regeneration of ferrous (Fe(II)). In this work, we report a novel iron(Fe)-based conjugated polymer capable of simultaneously achieving 2-electron photocatalytic oxygen activation and Fe(III) reduction, thereby enabling efficient degradation of organic pollutants. The underlying mechanism of the accelerated Fe(III)/Fe(II) cycle and enhanced degradation performance within this system is also elucidated. The polymer is constructed using a planar conjugated pyrene (Py) unit as the electron donor, which facilitates electron transfer for the reduction of Fe(III) to Fe(II) during H₂O₂ activation. Thiophene (Tp) and dibenzo[b,d]thiophene-s,s-dioxide (BDTO) are incorporated as the π-spacer and electron acceptor, respectively. The optimized Fe-Py-Tp-BDTO catalyst demonstrated outstanding performance, with an apparent rate constant of 0.14 min^-1 for 4-chlorophenol degradation and a mineralization rate of 79.1%, which significantly surpasses those of current photocatalysts. Quenching experiments confirmed that hydroxyl radicals and holes are the predominant reactive species responsible for pollutant removal. This work successfully establishes a heterogeneous photocatalysis-self-Fenton system with a highly efficient Fe(III)/Fe(II) cycle, thereby broadening the practical application scope of conventional Fenton technology.

Key words: Fe-Py-Tp-BDTO, Heterogeneous photocatalysis-self-Fenton, Fe(III)/Fe(II) cycle, Pollutant degradation, Photocatalyst

Rong Ji, Jingran Yi, Xinyu Sun, Yuming Dong, Chengsi Pan, Hui Zhao, Yongfa Zhu. Enhanced Fe(III)/Fe(II) cycle in heterogeneous photocatalysis-self-Fenton system for organic pollutants degradation[J]. Chinese Journal of Catalysis, 2026, 91: 376-385.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(26)65034-6

https://www.cjcatal.com/EN/Y2026/V91/I12/376

Figures/Tables 5

Fig. 1. (a) The structure of Fe-Py-Tp-BDTO. (b) FT-IR spectra of Fe-Py-Tp-BDTO and Py-Tp-BDTO. (c) The XPS spectra of Fe 2p of Fe-Py-Tp-BDTO. (d) O 1s XPS spectra of Py-Tp-BDTO and Fe-Py-Tp-BDTO. (e) The quasi in-situ EPR spectra of Py-Tp-BDTO and Fe-Py-Tp-BDTO.

Fig. 2. (a) Time profiles of H2O2 production for all samples in 4-chlorophenol solution. (b) Degradation ability for 4-chlorophenol over different systems. (c) k-value and TOC removal rate for different systems. (d) Heterogeneous photocatalysis-self-Fenton (PSF) degradation curves at different pH. (e) Wide applicability for various organic pollutants over photocatalysis-self-Fenton system: removal rate within 30 min over Fe-Py-Tp-BDTO. (f) Heterogeneous photocatalysis-self-Fenton cycle performance (Condition: catalyst=0.6 g L-1, 4-chlorophenol=10 mg L-1, 300 W Xe lamp, AM1.5. Concentration of organic pollutants: 10 mg L-1, BPA: bisphenol A, CIP: ciprofloxacin; NOR: norfloxacin; PHE: phenol; TC: tetracycline).

Fig. 3. (a) Free radical capture degradation curve over Fe-Py-Tp-BDTO. (b) EPR spectra of DMPO-•OH for all systems. (c) •OH yield profile of systems. (d) •OH transformation rate over photocatalysis-self-Fenton system and Fenton technology (Condition: catalyst=0.6 g L-1, 4-chlorophenol=10 mg L-1, 300 W Xe lamp, AM 1.5G).

Fig. 4. Steady-state PL spectra (a) and transient photocurrent response (b) of Py-Tp-BDTO and Fe-Py-Tp-BDTO. (c) Surface potential of Py-Tp-BDTO and Fe-Py-Tp-BDTO. fs-TA spectra (d) and pseudocolor plots (e) of Fe-Py-Tp-BDTO (All the samples are tested under 400 nm laser pulse excitation in H2O). (f) Raman spectra of Fe-Py-Tp-BDTO.

Fig. 5. In-situ DRIFT spectra recorded during photocatalytic H2O2 evolution of Py-Tp-BDTO (a) and Fe-Py-Tp-BDTO (b). ESR spectra of Py-Tp-BDTO (c) and Fe-Py-Tp-BDTO (d)+H2O2. (e) Eads of O2 on active sites of Py-Tp-BDTO and Fe-Py-Tp-BDTO. (f) The free-energy diagrams of Fe-Py-Tp-BDTO (Condition: catalyst=0.6 g L-1, 300 W Xe lamp, AM 1.5G).

References

[1]	S. Li, R. Li, K. Dong, Y. Liu, X. Yu, W. Li, T. Liu, Z. Zhao, M. Zhang, B. Zhang, X. Chen, Chin. J. Catal., 2025, 76, 37-49.
[2]	S. Li, Y. Zhao, X. Zhang, Y. Liu, T. Liu, W. Li, Y. Hou, W. Jiang, B. Zhang, Adv. Fiber Mater., 2025, 7, 2032-2047.
[3]	S. Li, X. Li, Y. Liu, P. Zhang, J. Zhang, B. Zhang, Chin. J. Catal., 2025, 72, 130-142.
[4]	M. Tazik, M. H. Dehghani, K. Yaghmaeian, S. Nazmara, M. Salari, A. H. Mahvi, S. Nasseri, H. Soleimani, R. R. Karri, Sci. Rep., 2023, 13, 7831.
[5]	Z. Chen, J. Wang, B. Yang, J. Li, Z. Liang, X. Liu, Y. Bao, J. Cao, M. Xing, Nat. Water, 2025, 3, 334-344.
[6]	J. Cao, W. Zhang, W. Lv, M. Zhu, L. Liang, Z. Liang, Q. Liu, Y. Jiang, M. Xing, Sci. Bull., 2026, 71, 577-586.
[7]	T. Wang, C. Zhao, L. Meng, Y. Li, D. Wang, C.-C. Wang, Appl. Catal. B, 2023, 334, 122832.
[8]	P. Zhou, W. Ren, G. Nie, X. Li, X. Duan, Y. Zhang, S. Wang, Angew. Chem. Int. Ed., 2020, 59, 16517-16526.
[9]	L. Su, P. Wang, X. Ma, J. Wang, S. Zhan, Angew. Chem. Int. Ed., 2021, 60, 21261-21266.
[10]	C. Wang, Y. Gu, S. Wu, H. Yu, S. Chen, Y. Su, Y. Guo, X. Wang, H. Chen, W. Kang, X. Quan, Environ. Sci. Technol., 2020, 54, 1920-1928.
[11]	H. W. Kim, M. B. Ross, N. Kornienko, L. Zhang, J. Guo, P. Yang, B. D. McCloskey, Nat. Catal., 2018, 1, 282-290.
[12]	J. Ji, Q. Yan, P. Yin, S. Mine, M. Matsuoka, M. Xing, Angew. Chem. Int. Ed., 2021, 60, 2903-2908.
[13]	Y. Yao, Y. Pan, Y. Yu, Z. Yu, L. Lai, F. Liu, L. Wei, Y. Chen, Environ. Chem. Lett., 2022, 20, 3837-3859.
[14]	E. Brillas, Sep. Purif. Technol., 2022, 284, 120290.
[15]	V. Poza-Nogueiras, E. Rosales, M. Pazos, M. Á. Sanromán, Chemosphere, 2018, 201, 399-416.
[16]	P. Cao, X. Quan, K. Zhao, S. Chen, H. Yu, J. Niu, J. Hazard. Mater., 2020, 382, 121102.
[17]	C. Han, S. Xiang, S. Jin, C. Zhang, J.-X. Jiang, ACS Catal., 2023, 13, 204-212.
[18]	H. Che, J. Wang, P. Wang, Y. Ao, J. Chen, X. Gao, F. Zhu, B. Liu, JACS Au, 2023, 3, 1424-1434.
[19]	J. Wang, G. Ouyang, Y. Wang, X. Qiao, W.-S. Li, H. Li, Chem. Commun., 2020, 56, 1601-1604.
[20]	F. Yu, Z. Wang, S. Zhang, W. Wu, H. Ye, H. Ding, X. Gong, J. Hua, Nanoscale Adv., 2021, 3, 1699-1707.
[21]	Z.-A. Lan, W. Ren, X. Chen, Y. Zhang, X. Wang, Appl. Catal. B, 2019, 245, 596-603.
[22]	H. Zhao, Y. Dong, P. Sun, Y. Bai, C. Ru, X. Wu, Z. Li, X. Han, J. Wu, X. Pan, ACS Appl. Energy Mater., 2022, 5, 4631-4640.
[23]	W.-R. Wang, J. Li, Q. Li, Z.-W. Xu, L.-N. Liu, X.-Q. Chen, W.-J. Xiao, J. Yao, F. Zhang, W.-S. Li, J. Mater. Chem. A, 2021, 9, 8782-8791.
[24]	C. Han, S. Xiang, S. Jin, L.-W. Luo, C. Zhang, C. Yan, J.-X. Jiang, J. Mater. Chem. A, 2022, 10, 5255-5261.
[25]	L. Chen, C. Chen, Z. Yang, S. Li, C. Chu, B. Chen, Adv. Funct. Mater., 2021, 31, 2105731.
[26]	S. Li, K. Dong, M. Cai, X. Li, X. Chen, eScience, 2024, 4, 100208.
[27]	S. Li, C. Wang, K. Dong, P. Zhang, X. Chen, X. Li, Chin. J. Catal., 2023, 51, 101-112.
[28]	H. Wang, C. Yang, F. Chen, G. Zheng, Q. Han, Angew Chem. Int. Edit., 2022, 61, e202202328.
[29]	L. Li, Z. Yin, M. Cheng, L. Qin, S. Liu, H. Yi, M. Zhang, Y. Fu, L. Yang, C. Tang, X. Zhou, F. Xu, G. Zeng, C. Lai, J. Mater. Chem. A, 2022, 10, 12788-12804.
[30]	C. Adamo, D. Jacquemin, Chem. Soc. Rev., 2013, 42, 845-856.
[31]	Q. Zhi, W. Liu, R. Jiang, X. Zhan, Y. Jin, X. Chen, X. Yang, K. Wang, W. Cao, D. Qi, J. Jiang, J. Am. Chem. Soc., 2022, 144, 21328-21336.
[32]	C. Qin, X. Wu, L. Tang, X. Chen, M. Li, Y. Mou, B. Su, S. Wang, C. Feng, J. Liu, X. Yuan, Y. Zhao, H. Wang, Nat. Commun., 2023, 14, 5238.
[33]	R. Ji, Y. Dong, X. Sun, P. Li, R. Zhang, C. Pan, H. Zhao, Y. Zhu, Adv. Energy Mater., 2024, 14, 2401437.
[34]	F. Xiao, Z. Wang, J. Fan, T. Majima, H. Zhao, G. Zhao, Angew. Chem. Int. Ed., 2021, 60, 10375-10383.
[35]	M. Jing, H. Zhao, L. Jian, C. Pan, Y. Dong, Y. Zhu, J. Hazard. Mater., 2023, 449, 131017.
[36]	T. Lu, H. Zhao, L. Jian, R. Ji, C. Pan, G. Wang, Y. Dong, Y. Zhu, Environ. Res., 2023, 222, 115361.