Upcycling Expired Bismuth-Drugs as Low-Cost Practical Precatalysts for Sustainable Multi-Scenario Formate Electrosynthesis

Abstract

The pressing challenges of resource shortage and environmental issue demand innovative technologies that matching circular economies. Here, we proposed an integrated strategy that enables direct waste reuse and sustainable electrosynthesis by converting expired bismuth (Bi)-drugs into impressive precatalysts, achieving the efficient electro-upcycling of carbon dioxide to formate in a universal electrolyzer with a stabilized Faradaic efficiency exceeding 90%. Systematically, we evaluated a range of expired Bi-drugs without any pretreatment, confirming consistently superior catalytic performance comparable to the benchmark in a flow cell system. This finding provides crucial experimental evidence for the feasibility of nonsorted direct utilization of expired Bi-drugs. Furthermore, to broaden the scope toward practical application, we also assessed the impact of water quality and the feasibility of tandem electro-chemo synthesis by employing the formate-containing electrolyte, which, for instance, allowed for the value-added synthesis of benzimidazole in a yield of 85%. This work establishes a scalable sustainable paradigm for interdisciplinary, integrating waste upcycling, energy-efficient synthesis, and up–downstream resource optimization.

Keywords

CO₂-to-formate / electro-upcycling / expired bismuth-drugs / tandem value-added synthesis

References

[1] J. Lambert, “Pharmacology of Bismuth-Containing Compounds,” supplement, Reviews of Infectious Diseases 13, no. S8 (1991): S691–S695, https://doi.org/10.1093/clinids/13.Supplement_8.S691.

[2] A. Wagstaff, P. Benfield, and J. Monk, “Colloidal Bismuth Subcitrate,” Drugs 36, no. 2 (1988): 132–157, https://doi.org/10.2165/00003495-198836020-00002.

[3] H. Li, X. Wei, and H. Sun, “Molecular Insights Into Bismuth’s New Applications Against Antimicrobial Resistance and Coronaviruses,” Accounts of Chemical Research 59, no. 1 (2026): 1–12, https://doi.org/10.1021/acs.accounts.5c00471.

[4] Bismuth Drug Market Overview, https://www.wiseguyreports.com/reports/bismuth-drug-market.

[5] M. Chougale, Q. Saqib, M. Khan, et al., “Expired Pharmaceutical Drugs as Tribopositive Material for Triboelectric Nanogenerator,” Advanced Sustainable Systems 5, no. 12 (2021): 2100205, https://doi.org/10.1002/adsu.202100205.

[6] Technical Data for Bismuth, https://periodictable.com/Properties/A/CrustAbundance.an.html.

[7] H. Rabiee, P. Yan, H. Wang, Z. Zhu, and L. Ge, “Electrochemical CO₂ Reduction Integrated With Membrane/Adsorption-Based CO₂ Capture in Gas-Diffusion Electrodes and Electrolytes,” EcoEnergy 2, no. 1 (2024): 3–21, https://doi.org/10.1002/ece2.23.

[8] W. Kwon, D. Kim, Y. Lee, J. Jung, and D. H. Nam, “Advancements in Understanding Catalyst Reconstruction During Electrochemical CO₂ Reduction,” Exploration 5, no. 4 (2025): e20240019, https://doi.org/10.1002/EXP.20240019.

[9] J. Li, J. Huang, Z. Zhao, H. Zhu, P. Liao, and X. Chen, “Low-Coordination Indium Single-Atom Sites Anchored on a Metal-Organic Framework Single-Layer Boosts Electroreduction of CO₂ Into Formic Acid,” Angewandte Chemie International Edition 64, no. 36 (2025): e202511132, https://doi.org/10.1002/anie.202511132.

[10] S. Kar, A. Goeppert, and G. Prakash, “Integrated CO₂ Capture and Conversion to Formate and Methanol: Connecting Two Threads,” Accounts of Chemical Research 52, no. 10 (2019): 2892–2903, https://doi.org/10.1021/acs.accounts.9b00324.

[11] K. Sordakis, C. Tang, L. Vogt, et al., “Homogeneous Catalysis for Sustainable Hydrogen Storage in Formic Acid and Alcohols,” Chemical Reviews 118, no. 2 (2018): 372–433, https://doi.org/10.1021/acs.chemrev.7b00182.

[12] C. Zhang, X. Hao, J. Wang, et al., “Concentrated Formic Acid From CO₂ Electrolysis for Directly Driving Fuel Cell,” Angewandte Chemie International Edition 63, no. 13 (2024): e202317628, https://doi.org/10.1002/anie.202317628.

[13] X. Zhao, L. Yang, Y. Hao, et al., “Bismuth-Based Architectures Engineering for Selective CO₂ Electroreduction to Formate,” Chinese Chemical Letters 37, no. 5 (2025): 111904, https://doi.org/10.1016/j.cclet.2025.111904.

[14] L. Liu, Y. He, Q. Li, et al., “Self-Supported Bimetallic Array Superstructures for High-Performance Coupling Electrosynthesis of Formate and Adipate,” Exploration 4, no. 3 (2024): 20230043, https://doi.org/10.1002/EXP.20230043.

[15] W. Li, C. Yu, X. Tan, et al., “Beyond Leverage in Activity and Stability Toward CO₂ Electroreduction to Formate Over a Bismuth Catalyst,” ACS Catalysis 14, no. 10 (2024): 8050–8061, https://doi.org/10.1021/acscatal.4c01519.

[16] Z. Jiang, S. Ren, X. Cao, et al., “pH-Universal Electrocatalytic CO₂ Reduction With Ampere-Level Current Density on Doping-Engineered Bismuth Sulfide,” Angewandte Chemie International Edition 63, no. 32 (2024): e202408412, https://doi.org/10.1002/anie.202408412.

[17] J. Li, D. Li, S. Liu, J. Su, and L. Chen, “Recent Progress in the Moderation Strategies of Bi-Precatalyst Reconstruction for Electrocatalytic CO₂ Reduction to Formate,” Advanced Synthesis & Catalysis 367, no. 3 (2025): e70271, https://doi.org/10.1002/adsc.70271.

[18] Z. Tan, Z. Luo, Z. Wu, et al., “Metal-Phase Protection Suppresses Bi Leaching for Durable Acidic CO₂ Electroreduction to Formic Acid,” Angewandte Chemie International Edition 64, no. 2 (2025): e17618, https://doi.org/10.1002/anie.202517618.

[19] Q. Huang, Z. 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,” Advanced Materials 37, no. 7 (2025): 2415639, https://doi.org/10.1002/adma.202415639.

[20] C. Cao, D. Ma, J. Gu, et al., “Metal-Organic Layers Leading to Atomically Thin Bismuthene for Efficient Carbon Dioxide Electroreduction to Liquid Fuel,” Angewandte Chemie International Edition 59, no. 35 (2020): 15014–15020, https://doi.org/10.1002/anie.202005577.

[21] J. Xiao, D. Ma, X. Shen, S. Han, W. Wei, and Q. Zhu, “A Comparative Study Proposing Performance Benchmarks for Convoying Industrial CO₂-to-Formate Electroconversion,” Applied Catalysis A: General 703 (2025): 120362, https://doi.org/10.1016/j.apcata.2025.120362.

[22] H. Qing, E. Cline, Z. W. MengLi, T. D. Li, and K. A. Mirica, “Protonation Pathway for CO₂ Reduction Mediated by Coordinated H₂O on Active Sites,” Nature Communications 16, no. 1 (2025): 11263, https://doi.org/10.1038/s41467-025-66145-5.

[23] P. Lei, S. Liu, Q. Wen, et al., “Integrated “Two-in-One” Strategy for High-Rate Electrocatalytic CO₂ Reduction to Formate,” Angewandte Chemie International Edition 64, no. 3 (2025): e202415726, https://doi.org/10.1002/anie.202415726.

[24] Z. Ren, R. Wang, X. Pang, et al., “Crystalline/Amorphous Bi-BiNiO_x Electrocatalyst Enables Efficient Concurrent Formate Production From CO₂ and Methanol,” Nano Research 18, no. 11 (2025): 94908017, https://doi.org/10.26599/NR.2025.94908017.

[25] M. Li, T. Wang, W. Zhao, S. Wang, and Y. Zou, “A Pair-Electrosynthesis for Formate at Ultra-Low Voltage via Coupling of CO₂ Reduction and Formaldehyde Oxidation,” Nano-Micro Letters 14, no. 1 (2022): 211, https://doi.org/10.1007/s40820-022-00953-y.

[26] K. Trentelman, “A Note on the Characterization of Bismuth Black by Raman Microspectroscopy,” Journal of Raman Spectroscopy 40, no. 5 (2009): 585–589, https://doi.org/10.1002/jrs.2184.

[27] C. Cao, D. Ma, J. Jia, Q. Xu, X. Wu, and Q. Zhu, “Divergent Paths, Same Goal: A Pair-Electrosynthesis Tactic for Cost-Efficient and Exclusive Formate Production by Metal–Organic-Framework-Derived 2D Electrocatalysts,” Advanced Materials 33, no. 25 (2021): 2008631, https://doi.org/10.1002/adma.202008631.

[28] S. Liu, G. Wu, J. Jiang, et al., “Electrochemical Lattice Engineering of Bismuthene for Selective Glycine Synthesis,” Advanced Materials 37, no. 21 (2025): 2500843, https://doi.org/10.1002/adma.202500843.

[29] S. Wang, Y. Yan, Y. Du, et al., “Inhibiting the Deep Reconstruction of Ni-Based Interface by Coordination of Chalcogen Anions for Efficient and Stable Glycerol Electrooxidation,” Advanced Functional Materials 34, no. 39 (2024): 2404290, https://doi.org/10.1002/adfm.202404290.

[30] H. Wang, M. He, R. Li, et al., “Fluorine···Π Induced Alkyne Concentrating and Orderly Arranged Sulfonate-Adjusted Interfacial Water Structure Promote Alkene Electrosynthesis at Large Current Densities,” Angewandte Chemie International Edition 64, no. 40 (2025): e202513463, https://doi.org/10.1002/anie.202513463.

[31] Y. He, D. Ma, S. Zhou, M. Zhang, J. Tian, and Q. Zhu, “Integrated 3D Open Network of Interconnected Bismuthene Arrays for Energy-Efficient and Electrosynthesis-Assisted Electrocatalytic CO₂ Reduction,” Small 18, no. 1 (2022): 2105246, https://doi.org/10.1002/smll.202105246.

[32] Q. Gong, P. Ding, M. Xu, et al., “Structural Defects on Converted Bismuth Oxide Nanotubes Enable Highly Active Electrocatalysis of Carbon Dioxide Reduction,” Nature Communications 10, no. 1 (2019): 2807, https://doi.org/10.1038/s41467-019-10819-4.

[33] J. Pander,, M. Baruch, and A. Bocarsly, “Probing the Mechanism of Aqueous CO₂ Reduction on Post-Transition-Metal Electrodes Using ATR-IR Spectroelectrochemistry,” ACS Catalysis 6, no. 11 (2016): 7824–7833, https://doi.org/10.1021/acscatal.6b01879.

[34] X. Liu, H. Zheng, Q. Sun, et al., “Mastering the Lattice Strain in Bismuth-Based Electrocatalysts for Efficient CO₂-to-Formate Conversion,” Advanced Functional Materials 34, no. 34 (2024): 2400928, https://doi.org/10.1002/adfm.202400928.

[35] J. Wang, W. Tang, Z. Zhu, et al., “Stabilizing Lattice Oxygen of Bi₂O₃ by Interstitial Insertion of Indium for Efficient Formic Acid Electrosynthesis,” Angewandte Chemie International Edition 64, no. 13 (2025): e202423658, https://doi.org/10.1002/anie.202423658.

[36] C. Weng, C. Wang, Y. Song, et al., “In-situ Reconstruction of Active Bismuth for Enhanced CO₂ Electroreduction to Formate,” Chemical Engineering Journal 505 (2025): 159732, https://doi.org/10.1016/j.cej.2025.159732.

[37] M. Zhang, W. Wei, S. Zhou, et al., “Engineering a Conductive Network of Atomically Thin Bismuthene With Rich Defects Enables CO₂ Reduction to Formate With Industry-Compatible Current Densities and Stability,” Energy & Environmental Science 14, no. 9 (2021): 4998–5008, https://doi.org/10.1039/D1EE01495A.

[38] Y. Xiao, X. Lai, J. Feng, et al., “Self-Refreshing Bi-Based Active Sites for Efficient and Durable Electrochemical CO₂ Reduction,” Advanced Functional Materials 36 (2026): e23592, https://doi.org/10.1002/adfm.202523592.

[39] C. Liu, R. Li, Y. Zhang, et al., “Spatiotemporal Changes in Dissolved Organic Matter Chemodiversity and Its Interaction With Microbial Composition in Heavy-Metal Polluted River,” Water Research 288 (2026): 124738, https://doi.org/10.1016/j.watres.2025.124738.

[40] J. Eppinger and K. Huang, “Formic Acid as a Hydrogen Energy Carrier,” ACS Energy Letters 2, no. 1 (2017): 188–195, https://doi.org/10.1021/acsenergylett.6b00574.

[41] Z. Huang, Y. Wang, M. Qi, M. Conte, Z. Tang, and Y. Xu, “Interface Synergy of Exposed Oxygen Vacancy and Pd Lewis Acid Sites Enabling Superior Cooperative Photoredox Synthesis,” Angewandte Chemie International Edition 63, no. 47 (2024): e202412707, https://doi.org/10.1002/anie.202412707.

[42] Z. Yu, Q. Yao, W. An, et al., “Integrating CO₂ Electroreduction With Phenol Hydrogenation on an Oxygen-Affinity Tailored Catalyst,” Science Advances 11, no. 35 (2025): eady4981, https://doi.org/10.1126/sciadv.ady4981.

[43] C. Guo, W. Zhou, X. Lan, et al., “Electrochemical Upgrading of Formic Acid to Formamide via Coupling Nitrite Co-Reduction,” Journal of the American Chemical Society 144, no. 35 (2022): 16006–16011, https://doi.org/10.1021/jacs.2c05660.

[44] H. Bi, Z. Chen, C. Bi, S. Qu, and J. Liu, “Electroreductive Amination of Carboxylic Acids by Cobalt Catalysis,” Nature Communications 16, no. 1 (2025): 7167, https://doi.org/10.1038/s41467-025-62396-4.

[45] Y. Yu, J. Han, H. Li, et al., “CuPt Alloy Enabling the Tandem Catalysis for Reduction of HCOOH and NO₃-to Urea at High Current Density,” Advanced Materials 37, no. 14 (2025): 2419738, https://doi.org/10.1002/adma.202419738.

[46] J. Majhi and G. Molander, “Recent Discovery, Development, and Synthetic Applications of Formic Acid Salts in Photochemistry,” Angewandte Chemie International Edition 63, no. 4 (2024): e202311853, https://doi.org/10.1002/anie.202311853.

[47] F. Valentini, V. Kozell, C. Petrucci, et al., “Formic Acid, a Biomass-Derived Source of Energy and Hydrogen for Biomass Upgrading,” Energy & Environmental Science 12, no. 9 (2019): 2646–2664, https://doi.org/10.1039/C9EE01747J.

[48] H. Ning, Y. Chen, Z. Wang, et al., “Selective Upgrading of Biomass-Derived Benzylic Ketones by (Formic acid)-Pd/HPC-NH₂ System With High Efficiency Under Ambient Conditions,” Chem 7, no. 11 (2021): 3069–3084, https://doi.org/10.1016/j.chempr.2021.07.002.

[49] K. Caso, G. Sainz, M. Guerra, and A. Irabien, “Electroreduction of CO₂: Advances in the Continuous Production of Formic Acid and Formate,” ACS Energy Letters 8, no. 4 (2023): 1992–2024, https://doi.org/10.1021/acsenergylett.3c00489.

[50] G. M. Landwehr, B. Vogeli, C. Tian, et al., “A Synthetic Cell-Free Pathway for Biocatalytic Upgrading of Formate From Electrochemically Reduced CO₂,” Nature Chemical Engineering 3, no. 1 (2026): 57–69, https://doi.org/10.1038/s44286-025-00315-6.

[51] Benzimidazole Fungicide Market Overview, https://www.wiseguyreports.com/reports/benzimidazole-fungicide-market.

[52] R. Lu, Y. Liu, and Z. Wang, “Advances in the Understanding of Selective CO₂ Reduction Catalysis,” EcoEnergy 2, no. 4 (2024): 695–713, https://doi.org/10.1002/ece2.67.

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2026 The Author(s). EcoEnergy published by John Wiley & Sons Australia, Ltd on behalf of China Chemical Safety Association.