Unraveling in-situ electrochemical reconstruction of indium oxide catalysts with oxygen vacancy for enhanced electrocatalytic CO₂-to-formate conversion

Abstract

Indium-based materials have emerged as promising alternative catalysts for the selective electroreduction of CO₂ to formate, yet the optimal catalytic configuration remains elusive. Herein, theoretical calculation reveals that metallic indium over oxygen vacancy-containing In₂O₃ support (In/In₂O₃-V_O) possesses the lowest energy barriers (0.99 eV) for CO₂ reduction to formate. A rational air-annealing strategy applied to In³⁺-adsorbed resin is developed to synthesize indium oxide catalysts containing oxygen vacancy (R-In₂O₃). In-situ spectroscopy techniques confirm in-situ electrochemical reconstruction of the In/In₂O₃ configuration and the effective stabilization of the key reaction intermediate (HCOO*). Consequently, the catalyst delivers excellent CO₂-to-formate conversion performance, maintaining a current efficiency above 92% over 56 h of galvanostatic electrolysis at −250 mA·cm⁻². These insights provide an effective strategy for the rational design of high-performance and durable indium-based electrocatalysts for sustainable formate production.

Keywords

carbon dioxide electroreduction / indium oxide / formate / active sites / energy conversion

References

[1] Zhang X, Yang P. Advances in noble metal-modified g-C₃N₄ heterostructures toward enhanced photocatalytic redox ability. Int. J. Miner. Metall. Mater., 2024, 31(11): 2368.

[2] Rodriguez AG, Chen ZY, Pant D, Dendooven J. Effect of catalyst ink preparation on formate production from CO₂ electroreduction using Sn as electrocatalyst. Int. J. Miner. Metall. Mater., 2025, 32(9): 2270.

[3] Dutta N, Peter SC. Electrochemical CO₂ reduction in acidic media: A perspective. J. Am. Chem. Soc., 2025, 147(11): 9019.

[4] Shaw WJ, Kidder MK, Bare SR, et al.. A US perspective on closing the carbon cycle to defossilize difficult-to-electrify segments of our economy. Nat. Rev. Chem, 2024, 8(5): 376.

[5] Tian C, Dorakhan R, Wicks J, et al.. Progress and roadmap for electro-privileged transformations of bio-derived molecules. Nat. Catal., 2024, 7(4): 350.

[6] Qian CG, Li CQ, Huang P, et al.. Research progress of CO₂ capture and mineralization based on natural minerals. Int. J. Miner. Metall. Mater., 2024, 31(6): 1208.

[7] Liu X, Wang YF, Dai ZW, Gao DH, Zhao XB. Electrochemical reduction of carbon dioxide to produce formic acid coupled with oxidative conversion of biomass. J. Energy Chem., 2024, 92: 705.

[8] Z.M. Wei, J. Ding, Z.Y. Wang, et al., Enhanced electrochemical CO₂ reduction to formate over phosphate-modified In: Water activation and active site tuning, Angew. Chem. Int. Ed., 63(2024), No. 27, art. No. e202402070.

[9] Wang XY, Jan S, Wang ZY, Jin XB. Solid Bi₂O₃-derived nanostructured metallic bismuth with high formate selectivity for the electrocatalytic reduction of CO₂. Int. J. Miner. Metall. Mater., 2024, 31(4): 803.

[10] K. Yang, M. Li, T.Q. Gao, et al., An acid-tolerant metal-organic framework for industrial CO₂ electrolysis using a proton exchange membrane, Nat. Commun., 15(2024), No. 1, art. No. 7060.

[11] H.L. Huang, X. Ding, X.N. Mao, et al., Liquid metal alloys enable efficient formate electrosynthesis, Adv. Funct. Mater., 34(2024), No. 49, art. No. 2408966.

[12] B. Zhang, Y. Chang, P.L. Zhai, et al., Enriching metal–oxygen species and phosphate modulating of active sites for robust electrocatalytical CO2 reduction, Adv. Mater., 35(2023), No. 46, art. No. 2304379.

[13] Yang S, An HY, Arnouts S, et al.. Halide-guided active site exposure in bismuth electrocatalysts for selective CO₂ conversion into formic acid. Nat. Catal., 2023, 6(9): 796.

[14] J.G. Zhang, T.T. Fan, P.P. Huang, et al., Electro-reconstruction-induced strain regulation and synergism of Ag–In–S toward highly efficient CO₂ electrolysis to formate, Adv. Funct. Mater., 32(2022), No. 25, art. No. 2113075.

[15] Cheng CF, Liu TF, Wang Y, et al.. Amorphous Sn(HPO₄)₂-derived phosphorus-modified Sn/SnO_x core/shell catalyst for efficient CO₂ electroreduction to formate. J. Energy Chem., 2023, 81: 125.

[16] Wang XC, Zhang N, Guo SH, et al.. P-d orbital hybridization induced by asymmetrical FeSn dual atom sites promotes the oxygen reduction reaction. J. Am. Chem. Soc., 2024, 146(31): 21357.

[17] Shang HS, Liu D. Atomic design of carbon-based dual-metal site catalysts for energy applications. Nano Res., 2023, 16(5): 6477.

[18] X.C. Wang, N. Zhang, H.S. Shang, et al., Precisely designing asymmetrical selenium-based dual-atom sites for efficient oxygen reduction, Nat. Commun., 16(2025), No. 1, art. No. 470.

[19] L.L. Zhang, N. Zhang, H.S. Shang, et al., High-density asymmetric iron dual-atom sites for efficient and stable electrochemical water oxidation, Nat. Commun., 15(2024), No. 1, art. No. 9440.

[20] Wang WH, Wang XS, Ma ZG, et al.. Carburized In₂O₃ nanorods endow CO₂ electroreduction to formate at 1 A cm⁻². ACS Catal., 2023, 13(1): 796.

[21] Ning H, Fei X, Tan ZH, Wang WH, Yang ZX, Wu MB. In situ-fabricated In₂S₃-reduced graphene oxide nanosheet composites for enhanced CO₂ electroreduction to formate. ACS Appl. Nano Mater., 2022, 5(2): 2335.

[22] Grigioni I, Sagar LK, Li YC, et al.. CO₂ electroreduction to formate at a partial current density of 930 mA cm⁻² with InP colloidal quantum dot derived catalysts. ACS Energy Lett., 2021, 6(1): 79.

[23] Wang ZT, Zhou YS, Xia CF, Guo W, You B, Xia BY. Efficient electroconversion of carbon dioxide to formate by a reconstructed amino-functionalized indium–organic framework electrocatalyst. Angew. Chem. Int. Ed., 2021, 60(35): 19107.

[24] Jia BQ, Chen Z, Li CJ, et al.. Indium cyanamide for industrial-grade CO₂ electroreduction to formic acid. J. Am. Chem. Soc., 2023, 145(25): 14101.

[25] Shang HS, Wang T, Pei JJ, et al.. Design of a single-atom indium^δ+–N₄ interface for efficient electroreduction of CO₂ to formate. Angew. Chem. Int. Ed., 2020, 59(50): 22465.

[26] F. Gholampoursaadi, X. Zhi, S. Nour, J.Z. Liu, G.K. Li, and M. Mayyas, Surface enrichment in gallium–indium liquid alloys: Applied to CO₂ conversion, Adv. Funct. Mater., 34(2024), No. 34, art. No. 2316435.

[27] Z.T. Wang, D.Y. Liu, C.F. Xia, et al., Tip carbon encapsulation customizes cationic enrichment and valence stabilization for low K⁺ acidic CO₂ electroreduction, Nat. Commun., 16(2025), No. 1, art. No. 1754.

[28] Z.T. Wang, Y.S. Zhou, D.Y. Liu, et al., Carbon-confined indium oxides for efficient carbon dioxide reduction in a solid-state electrolyte flow cell, Angew. Chem. Int. Ed., 61(2022), No. 21, art. No. e202200552.

[29] Hong B, Fei HG, Li Z, Xiao JX, Guo CL, Xiao W. Rational integration of metallurgy and material towards In-based electrocatalyst for CO₂ reduction. J. Energy Chem., 2025, 108: 57.

[30] C. Qiu, K. Qian, J. Yu, et al., MOF-transformed In₂O_3−x@C nanocorn electrocatalyst for efficient CO₂ reduction to HCOOH, Nano Micro Lett., 14(2022), No. 1, art. No. 167.

[31] Cheng Q, Huang M, Xiao L, et al.. Unraveling the influence of oxygen vacancy concentration on electrocatalytic CO₂ reduction to formate over indium oxide catalysts. ACS Catal., 2023, 13(6): 4021.

[32] Perdew J, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys. Rev. Lett., 1996, 77(18): 3865.

[33] Blöchl P. Projector augmented-wave method. Phys. Rev. B, 1994, 50(24): 17953.

[34] Kresse G, Furthmüller J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B, 1996, 54(16): 11169.

[35] S. Grimme, J. Antony, S. Ehrlich, and H. Krieg, A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu, J. Chem. Phys., 132(2010), No. 15, art. No. 154104.

[36] M.S. Frei, C. Mondelli, R.G. Muelas, et al., Atomic-scale engineering of indium oxide promotion by palladium for methanol production via CO₂ hydrogenation, Nat. Commun., 10(2019), No. 1, art. No. 3377.

[37] V. Wang, N. Xu, J.C. Liu, G. Tang, and W.T. Geng, VASPKIT: A user-friendly interface facilitating high-throughput computing and analysis using VASP code, Comput. Phys. Commun., 267(2021), art. No. 108033.

[38] Gu J, Liu S, Ni WY, Ren WH, Haussener S, Hu XL. Modulating electric field distribution by alkali cations for CO₂ electroreduction in strongly acidic medium. Nat. Catal., 2022, 5(4): 268.

[39] Qin YY, Xia CF, Wu TT, et al.. Specific adsorption of alkaline cations enhances CO–CO coupling in CO₂ electroreduction. J. Am. Chem. Soc., 2024, 146(47): 32539.

[40] H.H. Wang, N. Wen, Y.Q. Wang, X.L. Jiao, Y.G. Xia, and D.R. Chen, Boosting electrochemical reduction of CO₂ to formate over oxygen vacancy stabilized copper–tin dual single atoms catalysts, Adv. Funct. Mater., 33(2023), No. 42, art. No. 2303473.

[41] G.R. Zhang, B. Tan, D.H. Mok, et al., Electrifying HCOOH synthesis from CO₂ building blocks over Cu–Bi nanorod arrays, PNAS, 121(2024), No. 29, art. No. e2400898121.

[42] Chen HC, Wen HB, Sun JL, et al.. Quantitative exploration of aging–precipitate–property relationship in Mg–Gd alloys. J. Mater. Sci. Technol., 2026, 245: 221.

[43] L.P. Xiao, R.S. Zhou, T.Q. Zhang, et al., Porous indium nanocrystals on conductive carbon nanotube networks for high-performance CO₂-to-formate electrocatalytic conversion, Energy Environ. Mater., 7(2024), No. 4, art. No. e12656.

[44] Y.Y. Zhang, Y.X. Chen, X.W. Wang, et al., Low-coordinated copper facilitates the *CH₂CO affinity at enhanced rectifying interface of Cu/Cu₂O for efficient CO₂-to-multicarbon alcohols conversion, Nat. Commun., 15(2024), No. 1, art. No. 5172.

[45] Zhang QX, Gao J, Wang XJ, et al.. Phase-stable indium sulfide achieves an energy conversion efficiency of 14.3% for solarassisted carbon dioxide reduction to formate. Joule, 2024, 8(5): 1501.

[46] Sun X, Yang XH, Lu YF, et al.. Hot extrusion-induced Mg–Ni–Y alloy with enhanced hydrogen storage kinetics. J. Mater. Sci. Technol., 2024, 202: 119.

[47] J.Y. Zhao, K. Huang, C.W. Liu, et al., Electro-induced crystallization over amorphous indium hydroxide gels toward amperelevel current density formate electrosynthesis, Adv. Funct. Mater., 34(2024), No. 24, art. No. 2316167.

[48] H. Liu, Y. Bai, M. Wu, et al., A regenerable Bi-based catalyst for efficient and stable electrochemical CO₂ reduction to formate at industrial current densities, Angew. Chem. Int. Ed., 63(2024), No. 50, art. No. e202411575.

[49] Zhu S, Zhao Y, Zhu TY, et al.. Selective CO₂ electroreduction to formate over oxide-derived in nanosheets under industrial-current-density. Rare Met., 2024, 43(11): 6105.

[50] J.H. Bi, P.S. Li, J.Y. Liu, et al., High-rate CO₂ electrolysis to formic acid over a wide potential window: An electrocatalyst comprised of indium nanoparticles on chitosan-derived graphene, Angew. Chem. Int. Ed., 62(2023), No. 36, art. No. e202307612.

[51] J.X. Zhu, J.T. Li, R.H. Lu, et al., Surface passivation for highly active, selective, stable, and scalable CO₂ electroreduction, Nat. Commun., 14(2023), No. 1, art. No. 4670.

[52] Q.Z. Huang, Z.Y. Qian, N. Ye, et al., In situ reconstructed hydroxyl-rich atomic-thin Bi₂O₂CO₃ enables ampere-scale synthesis of formate from CO₂ with activated water dissociation, Adv. Mater., 37(2025), No. 7, art. No. 2415639.

[53] Y.C. Li, E.P. Delmo, G.Y. Hou, et al., Enhancing local CO₂ adsorption by L-histidine incorporation for selective formate production over the wide potential window, Angew. Chem. Int. Ed., 62(2023), No. 49, art. No. e202313522.

[54] W.W. Cai, X.Y. Cao, Y.Q. Wang, S. Chen, J.Z. Ma, and J.T. Zhang, Spatial structure of electron interactions in high-entropy oxide nanoparticles for active electrocatalysis of carbon dioxide reduction, Adv. Mater., 36(2024), No. 45, art. No. 2409949.

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