REFERENCES
1. Yu, J.; Wang, J.; Ma, Y.; et al. Recent progresses in electrochemical carbon dioxide reduction on copper-based catalysts toward multicarbon products. Adv. Funct. Mater. 2021, 31, 2102151.
2. Jin, R.; Li, G.; Sharma, S.; Li, Y.; Du, X. Toward active-site tailoring in heterogeneous catalysis by atomically precise metal nanoclusters with crystallographic structures. Chem. Rev. 2021, 121, 567-648.
3. Wang, G.; Chen, J.; Ding, Y.; et al. Electrocatalysis for CO2 conversion: from fundamentals to value-added products. Chem. Soc. Rev. 2021, 50, 4993-5061.
4. Irie, T.; Sasaki, K.; Das, S.; Negishi, Y. Materials innovation and the changing face of photocatalytic and electrocatalytic carbon dioxide reduction research: from metal nanoclusters to extended frameworks. Angew. Chem. Int. Ed. Engl. 2025, 64, e202515667.
5. Huang, J.; Zhang, X.; Yang, J.; Yu, J.; Chen, Q.; Peng, L. Recent progress on copper-based bimetallic heterojunction catalysts for CO2 electrocatalysis: unlocking the mystery of product selectivity. Adv. Sci. 2024, 11, e2309865.
6. Nitopi, S.; Bertheussen, E.; Scott, S. B.; et al. Progress and perspectives of electrochemical CO2 reduction on copper in aqueous electrolyte. Chem. Rev. 2019, 119, 7610-72.
7. Hori, Y.; Kikuchi, K.; Suzuki, S. Production of CO and CH4 in electrochemical reduction of CO2 at metal electrodes in aqueous hydrogen carbonate solution. Chem. Lett. 1985, 14, 1695-8.
8. Hori, Y.; Kikuchi, K.; Murata, A.; Suzuki, S. Production of methane and ethylene in electrochemical reduction of carbon dioxide at copper electrode in aqueous hydrogencarbonate solution. Chem. Lett. 1986, 15, 897-8.
9. Hori, Y.; Murata, A.; Takahashi, R.; Suzuki, S. Enhanced formation of ethylene and alcohols at ambient temperature and pressure in electrochemical reduction of carbon dioxide at a copper electrode. J. Chem. Soc,. Chem. Commun. 1988, 24, 17-9.
10. Hori, Y.; Murata, A.; Takahashi, R. Formation of hydrocarbons in the electrochemical reduction of carbon dioxide at a copper electrode in aqueous solution. J. Chem. Soc.,. Faraday. Trans. 1. 1989, 85, 2309-26.
11. Kuhl, K. P.; Cave, E. R.; Abram, D. N.; Jaramillo, T. F. New insights into the electrochemical reduction of carbon dioxide on metallic copper surfaces. Energy. Environ. Sci. 2012, 5, 7050-9.
12. Kuhl, K. P.; Hatsukade, T.; Cave, E. R.; Abram, D. N.; Kibsgaard, J.; Jaramillo, T. F. Electrocatalytic conversion of carbon dioxide to methane and methanol on transition metal surfaces. J. Am. Chem. Soc. 2014, 136, 14107-13.
13. Peterson, A. A.; Nørskov, J. K. Activity descriptors for CO2 electroreduction to methane on transition-metal catalysts. J. Phys. Chem. Lett. 2012, 3, 251-8.
14. Lee, H.; Park, N.; Kong, T. H.; et al. Advancements in electrochemical methanol synthesis from CO2: mechanisms and catalyst developments. Nano. Energy. 2024, 130, 110099.
15. Gu, Z.; Shen, H.; Shang, L.; Lv, X.; Qian, L.; Zheng, G. Nanostructured copper-based electrocatalysts for CO2 reduction. Small. Methods. 2018, 2, 1800121.
16. Wang, Y.; Liu, J.; Wang, Y.; Al-Enizi, A. M.; Zheng, G. Tuning of CO2 reduction selectivity on metal electrocatalysts. Small 2017, 13, 1701809.
17. Zhao, J.; Xue, S.; Barber, J.; Zhou, Y.; Meng, J.; Ke, X. An overview of Cu-based heterogeneous electrocatalysts for CO2 reduction. J. Mater. Chem. A. 2020, 8, 4700-34.
18. Mrabet, A.; Merino-Garcia, I.; Perfecto-Irigaray, M.; Beobide, G.; Khaddor, M.; Albo, J. Green copper oxide photocathodes using plant extracts for an efficient photoelectrochemical CO2 conversion to alcohols. J. CO2. Util. 2025, 101, 103222.
19. Du, Y.; Sheng, H.; Astruc, D.; Zhu, M. Atomically precise noble metal nanoclusters as efficient catalysts: a bridge between structure and properties. Chem. Rev. 2020, 120, 526-622.
20. Kawawaki, T.; Okada, T.; Hirayama, D.; Negishi, Y. Atomically precise metal nanoclusters as catalysts for electrocatalytic CO2 reduction. Green. Chem. 2024, 26, 122-63.
21. Ghosh, M.; Sarma, R.; Kamiyama, M.; Kawawaki, T.; Biswas, S.; Negishi, Y. Next-generation CO2 electroreduction: the role of atomically precise nanoclusters and emerging catalytic strategies. Nanoscale. Horiz. 2025, 10, 1250-67.
22. Dinh, K. H.; Menisa, L. T.; Warkentin, H.; Nguyen, T. N.; Dinh, C. T. Metal cluster catalysts for electrochemical CO2 reduction. ACS. Catal. 2025, 15, 5731-59.
23. Baghdasaryan, A.; Bürgi, T. Copper nanoclusters: designed synthesis, structural diversity, and multiplatform applications. Nanoscale 2021, 13, 6283-340.
24. Kawawaki, T.; Okada, T.; Takemae, K.; Tomihari, S.; Negishi, Y. Size-dependent carbon dioxide reduction activity of copper nanoparticle and nanocluster electrocatalysts. ChemNanoMat 2024, 10, e202300575.
25. Li, S.; Nagarajan, A. V.; Li, Y.; Kauffman, D. R.; Mpourmpakis, G.; Jin, R. The role of ligands in atomically precise nanocluster-catalyzed CO2 electrochemical reduction. Nanoscale 2021, 13, 2333-7.
26. Kauffman, D. R.; Alfonso, D.; Matranga, C.; Qian, H.; Jin, R. Experimental and computational investigation of Au25 clusters and CO2: a unique interaction and enhanced electrocatalytic activity. J. Am. Chem. Soc. 2012, 134, 10237-43.
27. Kauffman, D. R.; Thakkar, J.; Siva, R.; et al. Efficient electrochemical CO2 conversion powered by renewable energy. ACS. Appl. Mater. Interfaces. 2015, 7, 15626-32.
28. Biswas, S.; Negishi, Y. Exploring the impact of various reducing agents on Cu nanocluster synthesis. Dalton. Trans. 2024, 53, 9657-63.
29. Dhayal, R. S.; van Zyl, W. E.; Liu, C. W. Polyhydrido copper clusters: synthetic advances, structural diversity, and nanocluster-to-nanoparticle conversion. Acc. Chem. Res. 2016, 49, 86-95.
30. Nematulloev, S.; Huang, R. W.; Yin, J.; et al. [Cu15(PPh3)6(PET)13]2+: a copper nanocluster with crystallization enhanced photoluminescence. Small 2021, 17, e2006839.
31. Li, H.; Zhai, H.; Zhou, C.; et al. Atomically precise copper cluster with intensely near-infrared luminescence and its mechanism. J. Phys. Chem. Lett. 2020, 11, 4891-6.
32. Ke, F.; Song, Y.; Li, H.; Zhou, C.; Du, Y.; Zhu, M. Sub-nanometer Cu(i) clusters: coordination-modulated (Se vs. S) atom-packing mode and emission. Dalton. Trans. 2019, 48, 13921-4.
33. Tang, J.; Liu, C.; Zhu, C.; et al. High-nuclearity and thiol protected core-shell [Cu75(S-Adm)32]2+: distorted octahedra fixed to Cu15 core via strong cuprophilic interactions. Nanoscale 2023, 15, 2843-8.
34. Wang, L.; Yan, X.; Tian, G.; et al. Chiral copper-hydride nanoclusters: synthesis, structure, and assembly. Dalton. Trans. 2023, 52, 3371-7.
35. Dong, G.; Pan, Z.; Han, B.; et al. Multi-layer 3D Chirality and Double-Helical Assembly in a Copper Nanocluster with a Triple-Helical Cu15Core. Angew. Chem. Int. Ed. Engl. 2023, 62, e202302595.
36. Sun, C.; Mammen, N.; Kaappa, S.; et al. Atomically precise, thiolated copper-hydride nanoclusters as single-site hydrogenation catalysts for ketones in mild conditions. ACS. Nano. 2019, 13, 5975-86.
37. Han, B. L.; Liu, Z.; Feng, L.; et al. Polymorphism in Atomically Precise Cu23 nanocluster incorporating tetrahedral [Cu4]0 kernel. J. Am. Chem. Soc. 2020, 142, 5834-41.
38. Nguyen, T. A. D.; Jones, Z. R.; Goldsmith, B. R.; et al. A Cu25 nanocluster with partial Cu(0) character. J. Am. Chem. Soc. 2015, 137, 13319-24.
39. Das, A. K.; Biswas, S.; Wani, V. S.; Nair, A. S.; Pathak, B.; Mandal, S. [Cu18H3(S-Adm)12(PPh3)4Cl2]: fusion of Platonic and Johnson solids through a Cu(0) center and its photophysical properties. Chem. Sci. 2022, 13, 7616-25.
40. Li, Y. L.; Wang, J.; Luo, P.; et al. Cu14 Cluster with Partial Cu(0) character: difference in electronic structure from isostructural silver analog. Adv. Sci. 2019, 6, 1900833.
41. Jia, T.; Guan, Z. J.; Zhang, C.; et al. Eight-electron superatomic Cu31 nanocluster with chiral kernel and NIR-II emission. J. Am. Chem. Soc. 2023, 145, 10355-63.
42. Gao, P.; Du, J.; Hong, W.; et al. Observation of Body-Centered-Cubic Cu nanocluster with partial Cu(0) character. Small. Struct. 2025, 6, 2400397.
43. Biswas, S.; Shingyouchi, Y.; Kamiyama, M.; et al. Atomically precise [Cu23H4(SC7H7)18(PPh3)6] nanocluster: structural integration of johnson solids through a Cu(0) center and electrocatalytic functionality. J. Am. Chem. Soc. 2025, 147, 23733-42.
44. Zhang, L. P.; Fang, J. J.; Liu, Z.; Xie, Y. P.; Lu, X. Recent progress in atomically precise Cu-M alloy nanoclusters. Chem. Eur. J. 2025, 31, e202404281.
45. Deng, G.; Kim, J.; Bootharaju, M. S.; et al. Body-centered-cubic-kernelled Ag15Cu6 nanocluster with alkynyl protection: synthesis, total structure, and CO2 electroreduction. J. Am. Chem. Soc. 2023, 145, 3401-7.
46. Chen, X. Y.; Li, L. Y.; Zhao, L. C.; et al. Ag⁺-Mediated structural reconstruction of a metastable Cu35 cluster toward Cu-Ag heterometallic architectures for superior electrocatalytic CO2-to-ethanol conversion. Angew. Chem. Int. Ed. Engl. 2025, 64, e202511232.
47. Lee, S.; Bootharaju, M. S.; Deng, G.; et al. [Pt2Cu34(PET)22Cl4]2-: An atomically precise, 10-electron PtCu bimetal nanocluster with a direct Pt–Pt bond. J. Am. Chem. Soc. 2021, 143, 12100-7.
48. Peng, S. K.; Yang, H.; Luo, D.; Ning, G. H.; Li, D. A highly NIR emissive Cu16Pd1 nanocluster. Small 2024, 20, e2306863.
49. Zhang, X.; Guo, S. X.; Gandionco, K. A.; Bond, A. M.; Zhang, J. Electrocatalytic carbon dioxide reduction: from fundamental principles to catalyst design. Mater. Today. Adv. 2020, 7, 100074.
50. Zhang, Y.; Guo, S.; Zhang, X.; Bond, A. M.; Zhang, J. Mechanistic understanding of the electrocatalytic CO2 reduction reaction - new developments based on advanced instrumental techniques. Nano. Today. 2020, 31, 100835.
51. Sun, Z.; Ma, T.; Tao, H.; Fan, Q.; Han, B. Fundamentals and challenges of electrochemical CO2 reduction using two-dimensional materials. Chem 2017, 3, 560-87.
52. Sikdar, N. Electrochemical CO2 reduction reaction: comprehensive strategic approaches to catalyst design for selective liquid products formation. Chemistry 2024, 30, e202402477.
53. Chang, B.; Pang, H.; Raziq, F.; et al. Electrochemical reduction of carbon dioxide to multicarbon (C2+) products: challenges and perspectives. Energy. Environ. Sci. 2023, 16, 4714-58.
54. Tang, Q.; Lee, Y.; Li, D. Y; et al. Lattice-hydride mechanism in electrocatalytic CO2 reduction by structurally precise copper-hydride nanoclusters. J. Am. Chem. Soc. 2017, 139, 9728-36.
55. Shingyouchi, Y.; Ogami, M.; Biswas, S.; et al. Ligand-dependent intracluster interactions in electrochemical CO2 reduction using Cu14 nanoclusters. Small 2025, 21, e2409910.
56. Liu, L. J.; Wang, Z. Y.; Wang, Z. Y.; Wang, R.; Zang, S. Q.; Mak, T. C. W. Mediating CO2 electroreduction activity and selectivity over atomically precise copper clusters. Angew. Chem. Int. Ed. Engl. 2022, 61, e202205626.
57. Han, B. L.; Zhao, L. C.; Yuan, Z. R.; et al. Dipropyne-modified N-heterocyclic carbene stabilized atomically precise copper(I) nanocluster catalysts for CO2 electroreduction. Adv. Funct. Mater. 2025, 35, 2500149.
58. Wu, Q. J.; Si, D. H.; Sun, P. P.; et al. Atomically precise copper nanoclusters for highly efficient electroreduction of CO2 towards hydrocarbons via breaking the coordination symmetry of cu site. Angew. Chem. Int. Ed. Engl. 2023, 62, e202306822.
59. Biswas, S.; Tanaka, T.; Song, H.; et al. Highly selective methanol synthesis using electrochemical CO2 reduction with defect-engineered Cu58 nanoclusters. Small. Sci. 2024, 5, 2400465.
60. Biswas, S.; Hossian, S.; Kosaka, T.; et al. Nested Keplerian architecture of [Cu58H20(SPr)36(PPh3)8]2+nanoclusters. Chem. Commun. 2023, 59, 9336-9.
61. Li, S.; Yan, X.; Tang, J.; et al. Cu26 nanoclusters with quintuple ligand shells for CO2 electrocatalytic reduction. Chem. Mater. 2023, 35, 6123-32.
62. Chen, A.; Kang, X.; Jin, S.; Du, W.; Wang, S.; Zhu, M. Gram-scale preparation of stable hydride M@Cu24 (M = Au/Cu) nanoclusters. J. Phys. Chem. Lett. 2019, 10, 6124-8.
63. Yuan, P.; Chen, R.; Zhang, X.; et al. Ether-Soluble Cu53 nanoclusters as an effective precursor of high-quality CuI films for optoelectronic applications. Angew. Chem. Int. Ed. Engl. 2019, 58, 835-9.
64. Ghosh, A.; Huang, R. W.; Alamer, B.; et al. [Cu61(StBu)26S6Cl6H14]+: a core-shell superatom nanocluster with a Quasi-J36 Cu19 core and an “18-Crown-6” metal-sulfide-like stabilizing belt. ACS. Materials. Lett. 2019, 1, 297-302.
65. Xie, Y.; Liu, L. J.; Lu, Q.; Wu, W.; He, J.; Wang, Y. Tuning Cu nanocluster size for methane production in a bipolar membrane CO2 electrolyzer. Energy. Fuels. 2025, 39, 17661-8.
66. Han, C.; Yang, T.; Fang, Y.; et al. Steering the product selectivity of CO2 electroreduction by single atom switching in isostructural copper nanocluster catalysts. Angew. Chem. Int. Ed. Engl. 2025, 64, e202503417.
67. Li, J. K.; Dong, J. P.; Liu, S. S.; et al. Promoting CO2 electroreduction to hydrocarbon products via sulfur-enhanced proton feeding in atomically precise thiolate-protected Cu clusters. Angew. Chem. Int. Ed. Engl. 2024, 63, e202412144.
68. Handoko, A. D.; Li, K.; Tang, J. Recent progress in artificial photosynthesis: CO2 photoreduction to valuable chemicals in a heterogeneous system. Curr. Opin. Chem. Eng. 2013, 2, 200-6.
69. Dong, J. P.; Xu, Y.; Zhang, X. G.; et al. Copper-sulfur-nitrogen cluster providing a local proton for efficient carbon dioxide photoreduction. Angew. Chem. Int. Ed. Engl. 2023, 62, e202313648.
70. Wang, Y.; Qu, Y.; Qu, B.; et al. Construction of six-oxygen-coordinated single Ni sites on g-C3N4 with boron-oxo species for photocatalytic water-activation-induced CO2 reduction. Adv. Mater. 2021, 33, 2105482.
71. Wang, S.; Xu, M.; Peng, T.; et al. Porous hypercrosslinked polymer-TiO2-graphene composite photocatalysts for visible-light-driven CO2 conversion. Nat. Commun. 2019, 10, 676.
72. Lu, M.; Zhang, M.; Liu, J.; et al. Confining and highly dispersing single polyoxometalate clusters in covalent organic frameworks by covalent linkages for CO2 photoreduction. J. Am. Chem. Soc. 2022, 144, 1861-71.
