Photo-enhanced Co single-atom catalyst with a staggered p-n heterojunction: unraveling its high oxygen catalytic performance in zinc-air batteries and fuel cells

doi:10.1016/S1872-2067(25)64704-8

Abstract

Abstract:

The sluggish kinetics of the oxygen reduction reaction (ORR) and high over potential of oxygen evolution reaction (OER) are big challenges in the development of high-performance zinc-air batteries (ZABs) and fuel cells. In this work, we report a rational design and a simple fabrication strategy of a photo-enhanced Co single-atom catalyst (SAC) comprising g-C₃N₄ coupled with cobalt-nitrogen-doped hierarchical mesoporous carbon (Co-N/MPC), forming a staggered p-n heterojunction that effectively improves charge separation and enhances electrocatalytic activity. The incorporation of Co SACs and g-C₃N₄ synergistically optimizes the photogenerated electron-hole pair separation, significantly boosting the intrinsic ORR-OER duplex activity. Under illumination, g-C₃N₄@Co-N/MPC exhibits an outstanding ORR half-wave potential (E_1/2) of 0.841 V (vs. RHE) in 0.1 mol L^-1 KOH and a low OER overpotential of 497.4 mV (vs. RHE) at 10 mA cm^-2 in 1 mol L^-1 KOH. Notably, the catalyst achieves an exceptional peak power density of 850.7 mW cm^-2 in ZABs and of 411 mW cm^-2 even in H₂-air fuel cell. In addition, g-C₃N₄@Co-N/MPC-based ZABs also show remarkable cycling stability exceeding 250 h. The advanced photo-induced charge separation at the p-n heterojunction facilitates faster electron transfer kinetics, and the mass transport owing to hierarchical mesoporous structure of Co-N-C, thereby reducing the overpotential and enhancing the overall energy conversion efficiency. This work provides a new perspective on designing next-generation of single-atom dispersed oxygen reaction catalysts, paving the way for high-performance photo-enhanced energy storage and conversion systems.

Key words: Co single-atom, Hierarchical mesoporous carbon, Photo-enhancement, p-n Heterojunction, Oxygen catalytic reaction

Zhaodi Wang, Yang Zhang, Junxuan Zhang, Nengneng Xu, Tuo Lu, Biyan Zhuang, Guicheng Liu, Woochul Yang, Hao Lei, Binglun Tian, Jinli Qiao. Photo-enhanced Co single-atom catalyst with a staggered p-n heterojunction: unraveling its high oxygen catalytic performance in zinc-air batteries and fuel cells[J]. Chinese Journal of Catalysis, 2025, 73: 311-321.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(25)64704-8

https://www.cjcatal.com/EN/Y2025/V73/I6/311

Figures/Tables 5

Fig. 1. (a) Schematic diagram of the synthesis procedure of g-C3N4@Co-N/MPC. (b) SEM images of Co-N/MPC. (c) HAADF-STEM image of g-C3N4@Co-N/MPC. (d) Elemental mapping images. (e,f) TEM images of g-C3N4@Co-N/MPC.

Fig. 2. Physical characterization of Co-N/MPC and g-C3N4@Co-N/MPC. (a) XRD pattern for Co-N/MPC and g-C3N4@Co-N/MPC. (b) Raman spectrum. XPS spectra of C 1s (c) and N 1s (d). (e) A comparison chart illustrating the nitrogen content across various types. (f) Co K-edge XANES spectra of g-C3N4@Co-N/MPC with reference spectra of Co foil, CoO and CoPc. (g) The Fourier transform of the Co K-edge EXAFS spectra for the g-C3N4@Co-N/MPC with reference spectra of Co foil, CoO and CoPc. (h) The WT spectra of Co K edge EXAFS for Co foil, CoO, CoPc and g-C3N4@Co-N/MPC.

Fig. 3. (a) The ORR LSV polarization curves of g-C3N4, Co-N/MPC and g-C3N4@Co-N/MPC in O2-saturated 0.1 mol L-1 KOH electrolyte solution (1600 rpm) under light and darkness. (b) Comparison of E1/2 and limit current density. (c) The corresponding Tafel slopes. (d) Percentages of H2O2 produced and the electron transfer numbers of g-C3N4@Co-N/MPC under light and darkness. (e) The OER LSV polarization curves of g-C3N4, Co-N/MPC and g-C3N4@Co-N/MPC in 1 mol L-1 KOH electrolyte solution (1600 rpm) under light and darkness. (f) The corresponding Tafel slopes. (g) Comparison of bifunctional OER and ORR activity of g-C3N4@Co-N/MPC with other catalysts. (h) Comparison of ΔE. (i) Double-layer capacity of g-C3N4@Co-N/MPC under light and darkness.

Fig. 4. (a-c) Mott-Schottky plot of g-C3N4 (a), Co-N/MPC (b) and g-C3N4@Co-N/MPC (c). (d) UV-vis spectra. (e) Tauc plots. (f) Band structure diagram of g-C3N4@Co-N/MPC.

Fig. 5. Testing a complete zinc-air battery with photocatalyst g-C3N4@Co-N/MPC under light and darkness. (a) Schematic diagram of a zinc air battery. (b) OCV curves. (c) Discharge polarization curve and the corresponding power density curve. (d) Specific capacity plot. (e) The rate discharge test. (f) Comparison of zinc-air battery performance with various catalysts. (g) Polarization voltage curves for charging and discharging at 10 mA cm-2 constant currents. (h) Discharge polarization curves and the corresponding power density curves of a fuel cell under illumination and darkness.

References

[1]	G. Nazir, A. Rehman, J. H. Lee, C. H. Kim, J. Gautam, K. Heo, S. Hussain, M. Ikram, A. A. AlObaid, S.-Y. Lee, S.-J. Park, Nano-Micro Lett., 2024, 16, 138.
[2]	S. Chen, H. Ren, Y. Qiu, C. Luo, Q. Zhao, W. Yang, J. Power Sources, 2023, 573, 233116.
[3]	A. S. Jamadar, R. Sutar, S. Patil, R. Khandekar, J. B. Yadav, Mater. Rep. Energy, 2024, 4, 100283.
[4]	L. Qiao, X. Wang, R. Xu, C. Zhang, K. Chen, K. Tong, H. Wang, S. Dai, L. Chu, M. Huang, Mater. Today Energy, 2023, 37, 101398.
[5]	J. Li, H. Xue, N. Xu, X. Zhang, Y. Wang, R. He, H. Huang, J. Qiao, Mater. Rep. Energy, 2022, 2, 100090.
[6]	W. Y. Wong, M. A. A. Abdul Rani, K. S. Loh, K. L. Lim, L. J. Minggu, Curr. Opin. Green Sustain. Chem., 2025, 52, 101001.
[7]	P. Phogat, B. Chand, Shreya, R. Jha, S. Singh, Int. J. Hydrogen Energy, 2025, 109, 465-485.
[8]	Y. Wang, S. Qin, F. Ma, C. Wang, W. He, B. Zhang, H. Li, Renewable Energy, 2025, 246, 122885.
[9]	X. Wang, L. Peng, N. Xu, M. Wu, Y. Wang, J. Guo, S. Sun, J. Qiao, ACS Appl. Mater. Interfaces, 2020, 12, 52836-52844.
[10]	S. Pan, Z. Ma, W. Yang, B. Dongyang, H. Yang, S. Lai, F. Dong, X. Yang, Z. Lin, Mater. Rep. Energy, 2023, 3, 100212.
[11]	X. Tang, F. Li, F. Li, Y. Jiang, C. Yu, Chin. J. Catal., 2023, 52, 79-98.
[12]	D. Du, S. Zhao, Z. Zhu, F. Li, J. Chen, Angew. Chem. Int. Ed., 2020, 59, 18140-18144.
[13]	Z. Jiang, Z. Li, Q. He, S. Han, Y. Liu, H. Zhu, X. Yuan, Mater. Rep. Energy, 2024, 4, 100267.
[14]	Y. Zhang, N. Xu, B. Gong, X. Ye, Y. Yang, Z. Wang, B. Zhuang, M. Wang, W. Yang, G. Liu, J. K. Lee, J. Qiao, Chin. J. Catal., 2025, 68, 300-310.
[15]	L. Hu, Y. Zhang, Q. Lin, F. Cao, W. Mo, S. Zhong, H. Lin, L. Xie, L. Zhao, S. Bai, Chin. J. Catal., 2025, 68, 311-325.
[16]	X. Lu, P. Yang, Y. Wan, H. Zhang, H. Xu, L. Xiao, R. Li, Y. Li, J. Zhang, M. An, Coord. Chem. Rev., 2023, 495, 215400.
[17]	C. Ye, L. Zhang, Y. Shen, ACS Mater. Lett., 2024, 6, 2858-2887.
[18]	K. Liu, J. Fu, Y. Lin, T. Luo, G. Ni, H. Li, Z. Lin, M. Liu, Nat. Commun., 2022, 13, 2075.
[19]	M. Zhang, H. Li, J. Chen, F.-X. Ma, L. Zhen, Z. Wen, C.-Y. Xu, Small, 2022, 18, 2202476.
[20]	S. Liang, L. C. Zou, L. J. Zheng, F. Li, X. X. Wang, L. N. Song, J. J. Xu, Adv. Energy Mater., 2022, 12, 2103097.
[21]	L. Zhao, Z. Zhang, Z. Zhu, P. Li, J. Jiang, T. Yang, P. Xiong, X. An, X. Niu, X. Qi, J.-S. Chen, R. Wu, Chin. J. Catal., 2023, 51, 216-224.
[22]	H. Gao, K. Liu, T. Luo, Y. Chen, J. Hu, J. Fu, M. Liu, Chin. J. Catal., 2022, 43, 832-838.
[23]	N. Song, J. Jiang, S. Hong, Y. Wang, C. Li, H. Dong, Chin. J. Catal., 2024, 59, 38-81.
[24]	F. Dong, C. Liu, M. Wu, J. Guo, K. Li, J. Qiao, ACS Sustainable Chem. Eng., 2019, 7, 8587-8596.
[25]	X. Dong, X. Luo, X. Yang, M. Wang, W. Xiao, Y. Liu, N. Xu, W. Yang, G. Liu, J. Qiao, J. Colloid Interface Sci., 2024, 672, 32-42.
[26]	P. Jiang, Y. Wang, Y. Li, L. Dai, N. Xu, J. Qiao, D. Ruan, Sep. Purif. Technol., 2024, 341, 126813.
[27]	Y. Wang, B. Yu, K. Liu, X. Yang, M. Liu, T.-S. Chan, X. Qiu, J. Li, W. Li, J. Mater. Chem. A, 2020, 8, 2131-2139.
[28]	M. Zhang, H. Li, J. Chen, F. X. Ma, L. Zhen, Z. Wen, C. Y. Xu, Adv. Funct. Mater., 2023, 33, 2370280.
[29]	J. Zhu, L. Huang, F. Bao, G. Chen, K. Song, Z. Wang, H. Xia, J. Gao, Y. Song, C. Zhu, F. Lu, T. Zheng, M. Ji, Mater. Rep. Energy, 2024, 4, 100245.
[30]	B. Zhou, N. Xu, L. Wu, D. Cai, E. H. Yu, J. Qiao, Green Energy Environ., 2024, 9, 1835-1846.
[31]	T. Lu, N. Xu, L. Guo, B. Zhou, L. Dai, W. Yang, G. Liu, J. K. Lee, J. Qiao, Adv. Fiber Mater., 2024, 6, 1108-1121.
[32]	J. Wang, W. H. Xuan, Q. He, J. X. Jiang, Y. Y. Zhou, Y. Nie, Q. Liao, M. H. Shao, W. Ding, Z. D. Wei, J. Electrochem., 2023, 29, 2215003.
[33]	X. Luo, Z. Zheng, B. Hou, X. Xie, C. C. Wang, RSC Adv., 2023, 13, 18888-18897.
[34]	K. Fu, Y. Wang, L. Mao, X. Yang, J. Jin, S. Yang, G. Li, Chem. Eng. J., 2018, 351, 94-102.
[35]	W.-F. Wu, J.-G. Fan, Z.-H. Zhao, J.-M. Pan, J. Yang, X. Yan, Y. Zhan, Chin. J. Catal., 2024, 60, 178-189.
[36]	S. Hu, P. Qiao, X. Liang, G. Ba, X. Zu, H. Hu, J. Ye, D. Wang, Appl. Catal. B, 2024, 346, 123737.
[37]	X. Zhou, D. Xu, J. Huang, S. Tong, P. Qiao, Z. Zhang, Adv. Funct. Mater., 2024, 2418055, 1-8.
[38]	J. E. Park, M. J. Kim, M. S. Lim, S. Y. Kang, J. K. Kim, S. H. Oh, M. Her, Y. H. Cho, Y. E. Sung, Appl. Catal. B, 2018, 237, 140-148.
[39]	J. Tian, Q. Liu, A. M. Asiri, K. A. Alamry, X. Sun, ChemSusChem, 2014, 7, 2125-2130.
[40]	Z. G. Liu, J. Zhao, H. Yao, X. X. He, H. Zhang, Y. Qiao, X. Q. Wu, L. Li, S. L. Chou, Chem. Sci., 2024, 15, 8478-8487.
[41]	T. Wu, M. Y. Han, Z. J. Xu, ACS Nano, 2022, 16, 8531-8539.
[42]	K. Xiao, X. Jiang, S. Zeng, J. Chen, T. Hu, K. Yuan, Y. Chen, Adv. Funct. Mater., 2024, 34, 2405830.
[43]	G. Gan, S. Fan, X. Li, J. Wang, C. Bai, X. Guo, M. Tade, S. Liu, ACS Catal., 2021, 11, 14284-14292.
[44]	J. X. Flores-Lasluisa, D. Cazorla-Amorós, E. Morallón, Nanomaterials, 2024, 14, 1381.
[45]	T. H. Nguyen, P. K. L. Tran, D. T. Tran, T. N. Pham, N. H. Kim, J. H. Lee, Chem. Eng. J., 2022, 440, 135781.
[46]	S. Biniak, G. Szymański, J. Siedlewski, A. Świątkowski, Carbon, 1997, 35, 1799-1810.
[47]	C. Y. Li, R. Zhang, X. J. Ba, X. L.Jiang, Y. Y. Yang, J. Electrochem., 2023, 29, 2210241.
[48]	Y. Zhu, Z. Zhang, Z. Lei, Y. Tan, W. Wu, S. Mu, N. Cheng, Carbon, 2020, 167, 188-195.
[49]	F. Wang, Y. Zhou, S. Lin, L. Yang, Z. Hu, D. Xie, Nano Energy, 2020, 78, 105128.
[50]	X. Li, F. Dong, N. Xu, T. Zhang, K. Li, J. Qiao, ACS Appl. Mater. Interfaces, 2018, 10, 15591-15601.
[51]	J. Shi, M. Fan, J. Qiao, Y. Liu, Chem. Lett., 2014, 43, 1484-1486.
[52]	B. Ravel, M. Newville, J. Synchrotron Radiat., 2005, 12, 537-541.
[53]	S. I. Zabinsky, J. J. Rehr, A. Ankudinov, R. C. Albers, M. J. Eller, Phys. Rev. B, 1995, 52, 2995-3009.
[54]	H. Funke, A. C. Scheinost, M. Chukalina, Phys. Rev. B, 2005, 71, 094110.
[55]	Z. Li, F. Liu, C. Chen, Y. Jiang, P. Ni, N. Song, Y. Hu, S. Xi, M. Liang, Y. Lu, Nano Lett., 2023, 23, 1505-1513.
[56]	V. Reisecker, F. Flatscher, L. Porz, C. Fincher, J. Todt, I. Hanghofer, V. Hennige, M. Linares-Moreau, P. Falcaro, S. Ganschow, S. Wenner, Y.-M. Chiang, J. Keckes, J. Fleig, D. Rettenwander, Nat. Commun., 2023, 14, 2432.
[57]	S.-Y. Ham, H. Yang, O. Nunez-cuacuas, D. H. S. Tan, Y.-T. Chen, G. Deysher, A. Cronk, P. Ridley, J.-M. Doux, E. A. Wu, J. Jang, Y. S. Meng, Energy Storage Mater., 2023, 55, 455-462.
[58]	Y. Chen, R. Ren, Z. Wen, S. Ci, J. Chang, S. Mao, J. Chen, Nano Energy, 2018, 47, 66-73.
[59]	A. Hankin, J. C. Alexander, G. H. Kelsall, Phys. Chem. Chem. Phys., 2014, 16, 16176-16186.
[60]	S. Harrison, M. Hayne, Sci. Rep., 2017, 7, 11638.
[61]	S. Fu, C. Peng, Y. Luo, L. Cheng, X. Yang, Z. Jiao, J. Colloid Interface Sci., 2024, 664, 349-359.
[62]	Z. Zhong, P. Hansmann, Phys. Rev. X, 2017, 7, 011023.
[63]	L. Tian, X. Guan, Y. Dong, S. Zong, A. Dai, Z. Zhang, L. Guo, Environ. Chem. Lett., 2023, 21, 1257-1264.
[64]	R. Ren, G. Liu, J. Y. Kim, R. E. A. Ardhi, M. X. Tran, W. Yang, J. K. Lee, Appl. Catal. B, 2022, 306, 121096.
[65]	Y. Ren, D. Zeng, W. J. Ong, Chin. J. Catal., 2019, 40, 289-319.
[66]	H. Li, B. Sun, F. Yang, Z. Wang, Y. Xu, G. Tian, K. Pan, B. Jiang, W. Zhou, RSC Adv., 2019, 9, 7870-7877.
[67]	Z. Yin, R. He, H. Xue, J. Chen, Y. Wang, X. Ye, N. Xu, J. Qiao, H. Huang, Energy Mater., 2022, 2, 200021.