Preparation of Iron-Doped Carbon Dots for Enhanced Photocatalytic Carbon Dioxide Reduction

Abstract:

Photocatalytic reduction of carbon dioxide (CO₂) to solar fuel is a potential approach to overcome the problem of high CO₂ concentrations; however, the process still faces enormous challenges, such as low light absorption efficiency and high carrier recombination rates. Herein, Fe-doped carbon dots were prepared by a one-step hydrothermal method using sodium citrate, ethylenediamine, and FeCl₃·6H₂O as raw materials. The performances of the resulting materials toward the photocatalytic reduction of CO₂ were investigated and the results showed that Fe doping can regulate the energy band structure of CDs. However, the conduction band potential of Fe-carbon dots displayed no obvious influence except in terms of band gap. Moreover, Fe doping reduced the recombination rate of photo-generated carriers in CDs, increased the mobility of photo-generated carriers, and declined the resistance during the migration of photo-generated electrons. The photocatalytic reduction performances of CO₂ illustrated conversion yield of CO₂ to CH₃OH reaching 289.81 μmol·g (cat)^-1·h^-1 using Fe-CDs-13.0 catalyst, a value 2.36-fold higher than that of CDs. We found that Fe-CDs were synthesized by modulating the energy band structure of CDs. Fe-CDs improve visible light utilization and apply them to the photocatalytic reduction of CO₂.

• Periodical: Journal of Nano Research (Volume 88)
• Pages: 45-58
• DOI: https://doi.org/10.4028/p-6T6Yub
• Online since: June 2025
• Authors: Yong Qiang Dang*, Xi Tong Gao, Xiang Yu Feng, Bo Ni Li, Ke Ke Li, Jia Jia, Ya Ting Zhang
• Keywords: Carbon Dioxide Reduction, Carbon Dots, Fe-Doped, Methanol, Photocatalysis

References

[1] Y. Wang, X.T. Shang, J.N. Shen, Z.Z. Zhang, D.B. Wang, J.J. Lin, J.C.S. Wu, X.Z. Fu, X.X. Wang, C. Li, Direct and indirect Z-scheme heterostructure-coupled photosystem enabling cooperation of CO2 reduction and H2O oxidation, J. Nat. Commun. 11 (2020) 3043.

DOI: 10.1038/s41467-020-16742-3

[2] Y.T. Zhang, X.M. Ma, K.K. Li, J. Jia, M. Chen, Y.Q. Dang, L. Dai, g-C3N4/PP-CDs Heterostructure with Lewis acidity and alkalinity promoted photocatalytic CO2 reduction to CH3OH, J. Colloid. Surface. A. 705 (2025) 135676.

DOI: 10.2139/ssrn.4958122

[3] Z.X. Lin, J.Y. Zhang, Z. Xiong, Y.C. Zhao, Enhanced photocatalytic CO2 reduction in a twin reactor by separating triphase CO2 reduction and water oxidation reactions, J. Chem. Eng. 507 (2025) 160734.

DOI: 10.1016/j.cej.2025.160734

[4] Y. Zhao, H.H. Wang, L. Zeng, L.M. Huang, Understanding the roles of Ionic liquids in photocatalytic CO2 reduction, J. Mater. Chem. A. 8 (2025) 5546-5560.

DOI: 10.1039/d4ta07837c

[5] J. Kaur, S.C. Peter, Two-Dimensional Perovskites for Photocatalytic CO2 Reduction, J. Angewandte. Chemie. 2025 e202418708.

[6] Z.T. Zhang, G.Y. Yi, P. Li, X.X. Zhang, H.Y. Fan, X.D. Wang, C.X. Zhang, Y.L. Zhang, Engineering approach toward catalyst design for solar photocatalytic CO2 reduction: A critical review, J. Int. Energ. Res. 45 (2021) 9895-9913.

DOI: 10.1002/er.6603

[7] T.Y. Li, P. Wang, M. He, T.B. Zhang, C. Yang, Z.X. Li, Metal-organic frameworks for photocatalytical carbon dioxide reduction reaction, J. Coordin. Chem. Rev. 521 (2024) 216179.

DOI: 10.1016/j.ccr.2024.216179

[8] J.L. Ortiz Quiñonez, U. Pal, Interface engineered metal oxide heterojunction nanostructures in photocatalytic CO2 reduction: Progress and prospects, J. Coordin. Chem. Rev. 516 (2024) 215967.

DOI: 10.1016/j.ccr.2024.215967

[9] Z. Jiang, M.N. Guo, Z.Q. Yang, R.M. Fang, Z.Q. Wang, J.Y. Ran, Dioxygen atom co-doping g-C3N4 for boosted photoreduction activity of CO2 and mechanistic investigation, J. Mater. Chem. A. 12 (2024) 11591-11601.

DOI: 10.1039/d4ta00156g

[10] Y.P. Zou, Y.D. Shen, P.P. Gao, L. Liu, X.L. Chen, S.M. Sun, Q. An, Enhanced selective photocatalytic CO2 reduction to CO on AuPd decorated Bi2O2.33 nanosheets, J. Environ. Chem. Eng. 12 (2024) 112742.

DOI: 10.1016/j.jece.2024.112742

[11] Z.A. Shang, X.T. Feng, G.Z. Chen, R. Qin, Y.H. Han, Recent Advances on Single-Atom Catalysts for Photocatalytic CO2 Reduction, J. Small. 28 (2023) 04975.

DOI: 10.1002/smll.202304975

[12] Q.S. Wang, Y.C. Yuan, C.F. Li, Z.R. Zhang, C. Xia, W.G. Pan, L. Liu, R.T. Guo, Carbon quantum dot-modified TiO2/SrTiO3 heterojunction for boosting photocatalytic CO2 reduction, J. Renew. Energ. 231 (2024) 120997.

DOI: 10.1016/j.renene.2024.120997

[13] F.F. Tao, Y.L. Dong, L.G. Yang, NiO/g-C3N4 quantum dots for photocatalytic CO2 reduction, J. Appl. Surf. Sci. 638 (2023) 158044.

DOI: 10.1016/j.apsusc.2023.158044

[14] F.X. Zhao, X.Y. Li, M.X. Zuo, Y.S. Liang, P.F. Qin, H. Wang, Z.B. Wu, L. Luo, C. Liu, L. Leng, Preparation of photocatalysts decorated by carbon quantum dots (CQDs) and their applications: A review, J. Environ. Chem. Eng. 11 (2023) 108487.

DOI: 10.1016/j.jece.2023.109487

[15] R.M.S. Sendao, J.C.G. Esteves da Silva, L. Pinto da Silva, Applications of Fluorescent Carbon Dots as Photocatalysts: A Review, J. Catalysts. 13 (2023) 179.

DOI: 10.3390/catal13010179

[16] Z.D. Xu, X. Su, P.H. Yang, J.B. Zhong, M.J. Li, Efficient photocatalytic CO2 and Cr (VI) reduction on carbon quantum dots/carbon nitride heterojunctions, J. Fuel. 381 (2025) 133285.

DOI: 10.1016/j.fuel.2024.133285

[17] D. Kurniawan, H.Z. Xia, L.M. Dai, K. Ostriov, W.H. Chiang, Zero-dimensional nano-carbons: Synthesis, properties, and applications, J. Appl. Phys. Rev. 11 (2024) 021311.

DOI: 10.1063/5.0187310

[18] D. Xu, C.L. Yu, X.L. Peng, H. Yan, Y.B. Zhang, Recent advances in carbon quantum dot photocatalysis, J. Res. Chem. Intermediat. 50 (2024) 4597-4617.

DOI: 10.1007/s11164-024-05389-0

[19] Z. Liu, Z.J. Wang, S.J. Qing, N.N. Xue, S.P. Jia, L. Zhang, L. Li, N. Li, L.Y. Shi, J.Z. Chen, Improving methane selectivity of photo-induced CO2 reduction on carbon dots through modification of nitrogen-containing groups and graphitization, J. Appl. Catal. B: Environ. Energy. 232 (2018) 86-92.

DOI: 10.1016/j.apcatb.2018.03.045

[20] F.C. Sun, H. Maimaiti, Y.E. Liu, A. Awati, Preparation and photocatalytic CO2 reduction performance of silver nanoparticles coated with coal-based carbon dots, J. Energy Res. 42 (2018) 4458-4469.

DOI: 10.1002/er.4191

[21] S. Fang, Y. Xia, K.L. Lv, Q. Li, J. Sun, M. Li, Effect of carbon-dots modification on the structure and photocatalytic, J. Appl. Catal. B: Environ. Energy. 185 (2016) 225-232.

DOI: 10.1016/j.apcatb.2015.12.025

[22] N. Tejwan, A.K. Saini, A. Sharma, T. Abhishek Singh, N. Kumar, J. Das, Metal-doped and hybrid carbon dots: A comprehensive review on their synthesis and biomedical applications, J. Control. Release. 330 (2021) 132-150.

DOI: 10.1016/j.jconrel.2020.12.023

[23] L.P. Lin, Y.X. Luo, P.Y. Tsai, J.J. Wang, X, Chen, Metal ions doped carbon quantum dots: synthesis, physicochemical properties, and their applications, J. Trends. Anal. Chem. 103 (2018) 87-101.

DOI: 10.1016/j.trac.2018.03.015

[24] Y.Q. Dang, B.N. Li, X.Y. Feng, J. Jia, K.K. Li, Y.T. Zhang, Preparation of Iron‐Doped Carbon Dots and Their Application in Photocatalytic Reduction of Carbon Dioxide, J. ChemPhotoChem. 7 (2023) e202200156.

DOI: 10.1002/cptc.202200156

[25] J. Gao, C.Y. Xu, Y. Hu, F. Zhao, C.X. Shao, Y. Zhao, S. Chen, L.T. Qu, Unusual assembly and conversion of graphene quantum dots into crystalline graphite nanocapsules, J. Chem. Asian. 12 (2017) 1272-1276.

DOI: 10.1002/asia.201700297

[26] A.B. Bourlinos, A.K. Rathi, M.B. Gawande, K. Hola, A. Goswami, S. Kalytchuk, M.A. Karakassides, A. Kouloumois, D. Goswami, Y. Deligiannakis, E.P. Giannelis, R. Zboril, Fe (III)-functionalized carbon dots-Highly efficient photoluminescence redox catalyst for hydrogenations of olefins and decomposition of hydrogen peroxide, J. Appl. Mater. Today. 7 (2017) 179-184.

DOI: 10.1016/j.apmt.2017.03.002

[27] T.H. Hu, Z.S. Yin, J.W. Guo, C. Wang, Synthesis of Fe nanoparticles on polyaniline covered carbon nanotubes for oxygen reduction reaction, J. Power. Sources. 272 (2014) 661-671.

DOI: 10.1016/j.jpowsour.2014.08.124

[28] N. Liu, M.Q. Tang, J.X. Wu, L. Tang, W.Y. Huang, Q.T. Li, J.Q. Lei, X.D. Zhang, L. Wang, Boosting visible‐light photocatalytic performance for CO2 reduction via hydroxylated graphene quantum dots sensitized MIL‐101 (Fe), J. Adv. Mater. Interfaces. 7 (2020) 2000468.

DOI: 10.1002/admi.202000468

[29] L.H. Shi, L. Li, X.F. Li, G.M. Zhang, Y. Zhang, C. Dong, S.M. Shuang, Excitation-independent yellow-fluorescent nitrogen-doped carbon nanodots for biological imaging and paper-based sensing, J. Sensor. Actuat. B: Chem. 251 (2017) 234-241.

DOI: 10.1016/j.snb.2017.05.065

[30] Z.H. Liu, M.X. Ji, J.Z. Zhao, Y. Zhang, X. Sun, Y.F. Shao, H.M. Li, S. Yin, J.X. Xia, Dual modulation steering electron reducibility and transfer of bismuth molybdate nanoparticle to boost carbon dioxide photoreduction to carbon monoxide, J. Colloid. Interface. Sci. 610 (2022) 518-526.

DOI: 10.1016/j.jcis.2021.11.096

[31] S.M. Li, K. Ji, M. Zhang, C.S. He, J. Wang, Z.Q. Li, Boosting the photocatalytic CO2 reduction of metal-organic frameworks by encapsulating carbon dots, J. Nanoscale. 12 (2020) 9533-9540.

DOI: 10.1039/d0nr01696a

[32] S. Sahu, Y.M. Liu , P. Wang, C.E. Bunker, K.A. Shiral Fernando, W.K. Lewis, E.A. Guliants, F. Yang, J.P. Wang, Y.P. Sun, Visible-light photoconversion of carbon dioxide into organic acids in an aqueous solution of carbon dots, J. Langmuir. 30 (2014) 8631-8636.

DOI: 10.1021/la5010209

[33] X.Y. Kong, W.L. Tan, B.J. Ng, S.P. Chai, A.R. Mohamed, Harnessing Vis-NIR broad spectrum for photocatalytic CO2 reduction over carbon quantum dots-decorated ultrathin Bi2WO6 nanosheets, J. Nano. Research. 10 (2017) 1720-1731.

DOI: 10.1007/s12274-017-1435-4

[34] Y.O. Wang, X. Liu, X.Y. Han, R. Godin, J.L. Chen, W.Z. Zhou, C.R. Jiang, J.F. Thompson, K.B. Mustafa, S.A. Shevlin, J.R. Durrant, Z.X. Guo, J.W. Tang, Unique hole-accepting carbon-dots promoting selective carbon dioxide reduction nearly 100% to methanol by pure water, J. Nat. Commun. 11 (2020) 2531.

DOI: 10.1038/s41467-020-16227-3

[35] L.Y. Lin, S. Kavadiya, B.B. Karakocak, Y. Nie, R. Raliya, S.T. Wang, M.Y. Berezin, P. Biswas, ZnO1−x/carbon dots composite hollow spheres: Facile aerosol synthesis and superior CO2 photoreduction under UV, visible and near-infrared irradiation, J. Appl. Catal. B: Environ. Energy. 230 (2018) 36-48.

DOI: 10.1016/j.apcatb.2018.02.018

[36] H.T. Li, X.Y. Zhang, D.R. MacFarlane, Carbon quantum dots/Cu2O heterostructures for solar-light-driven conversion of CO2 to methanol, J. Adv. Energy. Mater. 5 (2015) 1401077.

DOI: 10.1002/aenm.201570024

[37] W.J. Sun, X.Y. Meng, C.J. Xu, J.Y. Yang, X.M. Liang, Y.J. Dong, C.Z. Dong, Y. Ding, Amorphous CoOx coupled carbon dots as a spongy porous bifunctional catalyst for efficient photocatalytic water oxidation and CO2 reduction, J. Chinese. Catal. 41 (2020) 1826-1836.

DOI: 10.1016/s1872-2067(20)63646-4

[38] Z.K. Liu, W.D. Hou, H.Z. Guo, Z.M. Wang, L. Wang, M.H. Wu, Functional group modulation in carbon quantum dots for accelerating photocatalytic CO2 reduction, J. ACS. Appl. Mater. Interfaces. 15 (2023) 33868-33877.

DOI: 10.1021/acsami.3c05440

[39] Q. Li, S.C. Wang, Z.X. Sun, Q.J. Tang, Y.Q. Liu, L.Z. Wang, H.Q. Wang, Z.B. Wu, Enhanced CH4 selectivity in CO2 photocatalytic reduction over carbon quantum dots decorated and oxygen doping g-C3N4, J. Nano. Research. 12 (2019) 2749-2759.

DOI: 10.1007/s12274-019-2509-2

[40] Y.O. Wang, R. Godin, J.R. Durrant, J.W. Tang, Efficient hole trapping in carbon dot/oxygen-modified carbon nitride heterojunction photocatalysts for enhanced methanol production from CO2 under neutral conditions, J. Angew. Chem. 60 (2021) 20811-20816.

DOI: 10.1002/anie.202105570