Species heterogeneity for efficient electrocatalytic nitrate reduction to ammonia

doi:10.1016/S1872-2067(26)65038-3

Abstract

Abstract:

Fe-based electrocatalysts are promising candidates for the electrochemical nitrate reduction reaction (NO₃RR) owing to their earth abundance and favorable catalytic activity. However, controlling the intrinsic heterogeneity of supported metal species remains challenging, often limiting active-site utilization and high mass-specific activity. Here we demonstrate a heterostructured Fe₁₊_n_/C catalyst composed of atomically dispersed Fe single atoms (Fe₁) and ultrasmall Fe nanoclusters (Fe_n) anchored on amorphous carbon via a controlled in-situ decomposition strategy. The synergistic coupling of Fe₁ and Fe_n sites enables efficient electron transfer and stepwise deoxygenation-hydrogenation, delivering a high NH₃ yield of 7889 μg mg_cat⁻¹ h⁻¹ and a Faradaic efficiency of 92.2% at -0.80 V vs. RHE, outperforming single-species counterparts (Fe₁/C and Fe_n/C). Density functional theory calculations reveal that Fe₁ sites facilitate nitrate adsorption and deoxygenation, whereas Fe_n clusters promote hydrogenation of intermediates. This work uncovers the mechanistic origin of the synergistic effect in Fe-based heterogeneous catalysts and provides a general strategy for designing multi-species active sites to accelerate tandem electrocatalytic reactions.

Key words: Electrocatalysts, Nitrate reduction reaction, Heterogeneity, Fe species, Single-atom

Kefu Zhang, Luxiao Zhang, Jianyi Chu, Cenyu Mei, Siyuan Liu, Guilan Fan, Fenrong Liu, Youngkook Kwon, Fenghua Bai, Wenhao Luo. Species heterogeneity for efficient electrocatalytic nitrate reduction to ammonia[J]. Chinese Journal of Catalysis, 2026, 85: 247-257.

×
share this article

Add to citation manager EndNote|Ris|BibTeX

URL: https://www.cjcatal.com/EN/10.1016/S1872-2067(26)65038-3

https://www.cjcatal.com/EN/Y2026/V85/I6/247

Figures/Tables 7

Scheme 1. Schematic illustration of the in-situ decomposition strategy for constructing Fe1/C, Fen/C and Fe1+n/C catalysts.

Fig. 1. (a) XRD patterns of FeB, C, Fe1/C, Fe1+n/C and Fen/C catalysts. (b-e) SEM images of C, Fe1/C, Fe1+n/C and Fen/C catalysts. (f) SEM-EDS elemental mapping of Fe, C, and O in Fe1+n/C catalyst. (g) N2 adsorption-desorption isotherms, and (h) corresponding BJH pore size distribution curves. (i) Raman spectra of C, Fe1/C, Fe1+n/C and Fen/C.

Fig. 2. (a-c) STEM images of the Fe1+n/C catalyst at different magnification. (d-f) HAADF-STEM images and corresponding EDX elemental mappings of Fe1+n/C catalyst. (g-i) AC-HAADF-STEM images of Fe1+n/C catalyst, Fe single-atoms in circles and nanoclusters in ellipse.

Fig. 3. (a) Schematic illustration of the H-type electrolyzer used for NO3RR. (b) LSV curves of Fe1+n/C, Fen/C, Fe1/C, FeB, and C catalysts in the presence and absence of nitrate. (c) Heatmaps of NH3 yield for the prepared catalysts. (d) Faradaic efficiency and NH3 yield of Fe1+n/C between -0.5 and -0.9 V vs. RHE. (e) Comparison of NH3 yields for Fe1+n/C, Fen/C, Fe1/C, FeB, and C catalysts between -0.5 and -0.9 V vs. RHE. (f) Ammonia yield rates normalized by Fe amount for Fe1+n/C, Fen/C, Fe1/C, and FeB catalysts. (g) Comparison of FE and NH3 yield of Fe1+n/C with previously reported Fe-based NO3RR catalysts. (h) Nyquist plots of Fe1+n/C, Fen/C, Fe1/C, FeB, and C catalysts. (i) Nitrate removal curve of the Fe1+n/C catalyst.

Fig. 4. (a) Faradaic efficiency and NH3 yield of Fe1+n/C over 10 successive cycles. (b) 1HNMR spectra of the 15NH4+ and 14NH4+ products formed over Fe1+n/C. (c) Long-term chronoamperometry tests of Fe1+n/C. (d) Comparison of NO3RR performance among Fe1+n/C, Fen/C, and Fe1/C catalysts. (e-f) In-situ infrared spectra spectrum of Fe1+n/C.

Fig. 5. (a) SEM, (b) STEM, and (c) HAADF-STEM images of Fe1+n/C after electrolysis. (d) Fe 2p XPS spectra of Fe1+n/C before and after electrolysis.

Fig. 6. (a) Calculated Gibbs free-energy diagrams for NO3RR process on Fe1/C, Fen/C and Fe1+n/C. (b) Optimized structural models and adsorption configurations of intermediates on Fe1+n/C.

References

[1]	Y. Ashida, K. Arashiba, K. Nakajima, Y. Nishibayashi, Nature, 2019, 568, 536-540.
[2]	D. R. MacFarlane, P. V. Cherepanov J,. Choi B. H. R., Suryanto R. Y., Hodgetts J. M., Bakker F. M., Ferrero Vallana A. N. Simonov, Joule, 2020, 4, 1186-1205.
[3]	X.-F. Cheng, J.-H. He, H.-Q. Ji, H.-Y. Zhang, Q. Cao, W.-J. Sun, C.-L. Yan, J.-M. Lu, Adv. Mater., 2022, 34, 2205767.
[4]	J. G. Chen, R. M. Crooks L. C., Seefeldt K. L., Bren R. M., Bullock M. Y., Darensbourg P. L., Holland B,. Hoffman M. J., Janik A. K., Jone M. G., Kanatzidis P,. King K. M., Lancaster S. V., Lymar P,. Pfromm W. F., Schneider R. R. Schrock, Science, 2018, 360, aar6611.
[5]	W. Xu G,. Fan J,. Chen J,. Li L,. Zhang S,. Zhu X,. Su F,. Cheng J. Chen, Angew. Chem. Int. Ed., 2020, 59, 3511-3516.
[6]	S. E. Braley, J. Xie Y,. Losovyj J. M. Smith, J. Am. Chem. Soc., 2021, 143, 7203-7208.
[7]	W. Wen S,. Fang Y,. Zhou Y,. Zhao P,. Li X.-Y. Yu, Angew. Chem. Int. Ed., 2024, 63, e202408382.
[8]	Y. Liu J,. Wei Z,. Yang L,. Zheng J,. Zhao Z,. Song Y,. Zhou J,. Cheng J,. Meng Z,. Geng J. Zeng, Nat. Commun., 2024, 15, 3619.
[9]	Z. Song, Y. Liu, Y. Zhong, Q. Guo, J. Zeng, Z. Geng, Adv. Mater., 2022, 34, 2204306.
[10]	S. Wang, X. Ji, S. Wang, P. Jing, X. Xu, B. Liu, J. Zhang, Adv. Funct. Mater., 2025, 35, 2502073.
[11]	J.-X. Liu, D. Richards, N. Singh, B. R. Goldsmith, ACS Catal., 2019, 9, 7052-7064.
[12]	S. Ren R.-T., Gao N. T., Nguyen L. Wang, Angew. Chem. Int. Ed., 2024, 63, e202317414.
[13]	Y. Liu X,. Zhao C,. Long X,. Wang B,. Deng K,. Li Y,. Sun F. Dong, Chin. J. Catal., 2023, 52, 196-206.
[14]	S.-J. Qian, H. Cao, X.-M. Lv, J. Li, Y.-G. Wang, J. Am. Chem. Soc., 2025, 147, 21032-21040.
[15]	Z.-Y. Wu, M. Karamad, X. Yong, Q. Huang, D. A. Cullen, P. Zhu, C. Xia, Q. Xiao, M. Shakouri, F.-Y. Chen, J. Y. Kim, Y. Xia, K. Heck, Y. Hu, M. S. Wong, Q. Li, I. Gates, S. Siahrostami, H. Wang, Nat. Commun., 2021, 12, 2870.
[16]	G. Chen, Y. Yuan, H. Jiang, S. Ren, L.-X. Ding, L. Ma, T. Wu, J. Lu, H. Wang, Nat. Energy, 2020, 5, 605-613.
[17]	J. Yu Z,. Xi J,. Su P,. Jing X,. Xu B,. Liu Y,. Wang J. Zhang, eScience, 2025, 5, 100350.
[18]	S. Li P,. Ma C,. Gao L,. Liu X,. Wang M,. Shakouri R,. Chernikov K,. Wang D,. Liu R,. Ma J. Wang, Energy Environ. Sci., 2022, 15, 3004-3014.
[19]	B. H. R,. Suryanto H.-L., Du D,. Wang J,. Chen A. N., Simonov D. R. MacFarlane Nat. Catal., 2019, 2, 290-296.
[20]	E. Murphy, Y. Liu, I. Matanovic, S. Guo, P. Tieu, Y. Huang, A. Ly, S. Das, I. Zenyuk, X. Pan, E. Spoerke, P. Atanassov, ACS Catal., 2022, 12, 6651-6662.
[21]	X. Guo R.-T., Gao S,. Ren N. T., Nguyen H,. Chen L,. Wu L. Wang, Nat. Commun., 2025, 16, 6220.
[22]	P. Gao Z.-H., Xue S.-N., Zhang D,. Xu G.-Y., Zhai Q.-Y., Li J.-S., Chen X.-H. Li, Angew. Chem. Int. Ed., 2021, 60, 20711-20716.
[23]	C. Tang, S.-Z. Qiao, Chem. Soc. Rev., 2019, 48, 3166-3180.
[24]	L. Chen, Y. Hao, J. Chu, S. Liu, F. Bai, W. Luo, Chin. J. Catal., 2024, 58, 25-36.
[25]	J. Wang, Z. Deng, T. Feng, J. Fan, W.-X. Zhang, Chem. Eng. J., 2021, 417, 129160.
[26]	L. Su D,. Han G,. Zhu H,. Xu W,. Luo L,. Wang W,. Jiang A,. Dong J. Yang, Nano Lett., 2019, 19, 5423-5430.
[27]	Y. Lan J,. Chen H,. Zhang W.-X., Zhang J,. Yang J. Mater. Chem. A, 2020, 8, 15853-15863.
[28]	G. Soloveichik, Nat. Catal., 2019, 2, 377-380.
[29]	Y. Zhao, J. Wan, C. Ling, Y. Wang, H. He, N. Yang, R. Wen, Q. Zhang, L. Gu, B. Yang, Z. Xiang, C. Chen, J. Wang, X. Wang, Y. Wang, H. Tao, X. Li, B. Liu, S. Zhang, D. Wang, Nature, 2025, 644, 668-675.
[30]	B. Qiao, A. Wang, X. Yang, L. F. Allard, Z. Jiang, Y. Cui, J. Liu, J. Li, T. Zhang, Nat. Chem., 2011, 3, 634-641.
[31]	C. Han S,. Zhang H,. Zhang Y,. Dong P,. Yao Y,. Du P,. Song X,. Gong W. Xu, eScience, 2024, 4, 100269.
[32]	H. Yang, L. Shang, Q. Zhang, R. Shi, G. I. N. Waterhouse, L. Gu, T. Zhang, Nat. Commun., 2019, 10, 4585.
[33]	Y. Wang, H. Yin, F. Dong, X. Zhao, Y. Qu, L. Wang, Y. Peng, D. Wang, W. Fang, J. Li, Small, 2023, 19, 2207695.
[34]	Y. Song, T. Liu, W. Feng, R. Li, Y. Guo, M. Li, L. Jiang, H. Matsumoto, C. Zeng, X. Zhang, G. Zou, Q. Liu, H. Lv, J. Yu, M. Liu, G. Wang, X. Bao, J. Am. Chem. Soc., 2024, 146, 31825-31835.
[35]	C. Dong, Y. Li, D. Cheng, M. Zhang, J. Liu, Y.-G. Wang, D. Xiao, D. Ma, ACS Catal., 2020, 10, 11011-11045.
[36]	L. Zeng, Z. Zhao, Q. Huang, C. Zhou, W. Chen, K. Wang, M. Li, F. Lin, H. Luo, Y. Gu, L. Li, S. Zhang, F. Lv, G. Lu, M. Luo, S. Guo, J. Am. Chem. Soc., 2023, 145, 21432-21441.
[37]	J. He Z,. Wu Q,. Gu Y,. Liu S,. Chu S,. Chen Y,. Zhang B,. Yang T,. Chen A,. Wang B. M., Weckhuysen T,. Zhang W. Luo, Angew. Chem. Int. Ed., 2021, 60, 23713-23721.
[38]	Y. Guo M,. Wang Q,. Zhu D,. Xiao D. Ma, Nat. Catal., 2022, 5, 766-776.
[39]	Y. Qin W,. Zhao C,. Xia L.-J., Yu F,. Song J,. Zhang T,. Wu R,. Cao S,. Ding B.-Y., Xia Y. Su, Angew. Chem. Int. Ed., 2024, 63, e202404763.
[40]	D.-L. Meng, M.-D. Zhang, D.-H. Si, M.-J. Mao, Y. Hou, Y.-B. Huang, R. Cao, Angew. Chem. Int. Ed., 2021, 60, 25485-25492.
[41]	X. Zhang, X. Liu, Z.-F. Huang, L. Guo, L. Gan, S. Zhang, M. Ajmal, L. Pan, C. Shi, X. Zhang, G. Yang, J.-J. Zou, ACS Catal., 2023, 13, 14670-14679.
[42]	L. Liu T,. Chen Z. Chen, Adv. Sci., 2024, 11, 2308046.
[43]	Z. Sun W,. Shi L. R., Smith N. F., Dummer H,. Qi Z,. Sun G. J. Hutchings, Nat. Commun., 2025, 16, 3935.
[44]	M. Peng, C. Dong, R. Gao, D. Xiao, H. Liu, D. Ma, ACS Cent. Sci., 2021, 7, 262-273.
[45]	C. Wang, Y. Zhang, H. Luo, H. Zhang, W. Li, W.-X. Zhang, J. Yang, Small Methods, 2022, 6, 2200790.
[46]	C. Li L,. Chen Y,. Suo B,. Kang H,. Su W,. Luo F. Bai, Chem. Eng. J., 2024, 480, 148240.
[47]	N. Shpaisman, E. R. Bauminger, S. Margel, J. Alloys Compd., 2008, 454, 89-96.
[48]	T. W. Smith, D. Wychick, J. Phys. Chem., 1980, 84, 1621-1629.
[49]	X. Teng, D. Si, L. Chen, J. Shi, eScience, 2024, 4, 100272.
[50]	B. Y. Yu, S.-Y. Kwak, J. Mater. Chem., 2010, 20, 8320-8328.
[51]	Y. Zhao, Z. Zhang, L. Liu, Y. Wang, T. Wu, W. Qin, S. Liu, B. Jia, H. Wu, D. Zhang, X. Qu, G. Qi, E. P. Giannelis, M. Qin, S. Guo, J. Am. Chem. Soc., 2022, 144, 20571-20581.
[52]	J. Cui D,. Zhang Z,. Liu C,. Li T,. Zhang S,. Yin Y,. Song H,. Li H,. Li C. Li, Nat. Commun., 2024, 15, 9458.
[53]	L. Zhang, Y. Wu, Z. Zhu, Y. Zhu, Y. Dong, M. Liang, H. Deng, Biochar, 2024, 6, 8.
[54]	Y. Xiong, Y. Wang, M. Sun, J. Chen, J. Zhou, F. Hao, F. Liu, P. Lu, X. Meng, L. Guo, Y. Liu, S. Xi, Q. Zhang, B. Huang, Z. Fan, Adv. Mater., 2024, 36, 2407889.
[55]	J. Zhang, C. Chen, R. Zhang, X. Wang, Y. Wei, M. Sun, Z. Liu, R. Ge, M. Ma, J. Tian, J. Colloid Interface Sci., 2024, 658, 934-942.
[56]	M. Wang, S. Li, Y. Gu, W. Xu, H. Wang, J. Sun, S. Chen, Z. Tie, J.-L. Zuo, J. Ma, J. Su, Z. Jin, J. Am. Chem. Soc., 2024, 146, 20439-20448.
[57]	X. Yao W,. Li D,. Cui M,. Dong G,. Shan M,. Zhang X,. Wang Z,. Su C. Sun, Nano Res., 2025, 18, 94907592.
[58]	Y. Liu S,. Huang J,. Lu S,. Niu P.-K., Shen Z,. Hu P,. Tsiakaras S. Gao, Adv. Funct. Mater., 2024, 34, 2411325.
[59]	T. Zhou, Y. Guan, C. He, L. Zhang, X. Sun, Z. Song, Q. Zhang, C. He, X. Jiang, Z. Luo, W. Xing, X. Ren, Carbon Energy, 2024, 6, e477.
[60]	J. Li Y,. Zhang C,. Liu L,. Zheng E,. Petit K,. Qi Y,. Zhang H,. Wu W,. Wang A,. Tiberj X,. Wang M,. Chhowalla L,. Lajaunie R,. Yu D. Voiry, Adv. Funct. Mater., 2022, 32, 2108316.