Constructing Monolayer Model Catalysts to Uncover the Distance Effect on CO2 Electroreduction towards Multi-Carbon Products

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Constructing Monolayer Model Catalysts to Uncover the Distance Effect on CO₂ Electroreduction towards Multi-Carbon Products

https://doi.org/10.21203/rs.3.rs-4376817/v1

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The interaction between adjacent active sites has significant effect on the performance of various electrocatalysis, e.g., CO₂ electroreduction. Unfortunately, little experimental work has been done to quantify this effect, due to the huge challenge in accurately regulating the distance between active sites. Herein, Cu-coordinated porphyrins with clear Cu–N₄ active sites are introduced as platform molecules to construct a monolayer structure on the Au(111) substrate. The distance between Cu centers can be accurately regulated in subnanometer level via changing the molecular ligands and the state of aggregation, and directly measured by scanning tunneling microscope (STM). The adjustable distance between adjacent Cu sites can bring forth fundamentally different selectivity of multi-carbon products in CO₂ electroreduction. Specifically, Cu sites with 0.98 nm inter-distance can still generate an appreciable 6.1% faraday efficiency (FE) of C₂H₄, and then drop dramatically to 1.2% with a 1.50 nm inter-distance. When the inter-distances between Cu sites are furtherly increased to 1.63 and 1.74 nm, the C − C coupling pathway will be totally blocked and thereby the selectivity of C₂H₄ will decline to almost negligible levels. These experimental results directly demonstrate the distance effect on CO₂ electroreduction for the first time. In addition, theoretical calculations also demonstrate a strong correlation between inter-site distance and selectivity of C₂H₄. This work might inspire the design of model catalysts to investigate the fundamental mechanism of various electrocatalytic reactions.

Physical sciences/Chemistry/Electrochemistry/Electrocatalysis

Physical sciences/Chemistry/Energy

Electrochemical CO₂ reduction reaction (CO₂RR) using sustainable energy sources has been regarded as one of the promising approaches to reduce the continuous accumulation of atmospheric CO₂ and generate a supply of value-added chemical fuels to regain the carbon balance [1-4]. Among the various reduction products from CO₂ reduction, multicarbon products are highly valuable as feedstocks in the chemical industry or as fuels for transportation purposes, e.g., ethylene, acetic acid, and ethanol [5-8]. However, the generation of multicarbon products is a complex process involving the multiple electron and proton transfer steps [9-11]. Furthermore, the crystal planes, size range and defects, or heteroatom doping all have significant impacts on the selectivity of multicarbon products [12-15]. Hence, it is necessary to construct a well-defined catalytic system to unravel the mechanism of multi carbon products.

Owing to relatively simple and uniform active centers, single-atom catalysts are frequently utilized to investigate the CO₂RR mechanism [16-17]. Recent discoveries show that the CO₂RR activity of single-atom catalysts can be tuned by modifying the coordination environment or electronic structure of the catalytic metals [18-19]. However, previous theoretical and experimental studies have demonstrated that the C-C coupling procedure is a crucial step towards the generation of multicarbon products [20-24]. When the active sites are far enough apart to form single-atom catalysts, only C1 products could be observed in many cases, e.g., CO, methanol or CH₄, and multicarbon products are occasionally obtained with closely adjacent single atoms [18, 25-26]. Unfortunately, the coordination environment or electronic structure of single atom catalysts are usually statistical results obtained from X-ray absorption fine structure (XAFS) [18]. Additionally, accurately regulating the distance between metallic sites still remains a huge challenge in the synthesis of single-atom catalysts.

Therefore, a model catalyst system with well-defined structure and regulatable inter-site distance is essential for the fundamental understanding of the parameters that influence the reaction pathway towards multicarbon products. In this case, molecular catalysts with metallic coordination centers could be an ideal candidate to construct this model catalyst system. Molecular catalysts possess good catalytic performance in various electrocatalytic reactions, e.g., oxygen reduction reaction (ORR), oxygen evolution reaction (OER) as well as CO₂RR [27-32]. The diversity of molecular ligands and coordinative metals can also enable it to adjust the distance between metal sites, and directly investigate the relationship between the inter-site distance and the selectivity of multicarbon products in CO₂RR procedure [33-34].

Herein, Cu-coordinated porphyrins with clear Cu–N4 active sites are introduced as platform molecules. The adsorbed monolayer of the Cu-coordinated porphyrins can be constructed via vapor deposition, self-assembly and on-surface polymerization procedure on Au(111) substrate. This well-defined monolayer structure on a flat and conductive Au(111) substrate is also suitable for STM investigation to directly measure the distance between Cu sites [35] and as electrode for CO₂RR. Furthermore, the distance between Cu centers can be accurately controlled to 0.98 nm, 1.50 nm, 1.63 nm, and 1.74 nm by changing the length of organic ligands and the states of aggregation. These as-synthesized catalysts were utilized in CO₂ electrolysis to evaluate selectivity of multi-carbon products. Both theoretical modelling and experimental evidence suggest the significance of the distance effect on the selectivity towards multi-carbon products.

Construction and characterization of monolayer model catalysts. A Cu-coordinated porphyrin molecule with clear and typical Cu-N4 structure, [meso-tetra(trimethylsilanylethynyl)porphinato]copper(II) (denoted as 1a, Fig. 1b), was synthesized through literature [36] and utilized as the precursor molecules. The Au(111) single crystal substrate was cleaned via cycles of Ar⁺ sputtering and annealing up to 500°C. Precursor 1a was deposited by organic molecular beam epitaxy (OMBE) at a sublimation temperature about 170°C onto the Au(111) substrates held at room temperature (Fig. 1a and Supplementary Fig. 1). These 1a molecules form a uniform monolayer self-assembly on Au(111). Each 1a molecule appears as a four-leaf-clover-like structure with four bright lobes, which representing the four -SiMe₃ (TMS) groups due to their spatial configuration. The assembled 1a layer is detected with an apparent height of 0.30 ± 0.01 nm (Supplementary Fig. 2), indicating the flat adsorption and monolayer configuration. Notably, the distance between two Cu centers in the 1a monolayer is measured to be 1.50 ± 0.03 nm (Fig. 1e).

Annealing the self-assembly molecules on Au(111) at 250°C would trigger a chemical reaction of 1a to 1b with a two-dimensional (2D) nanostructure (Fig. 1b). Almost all TMS groups (bright features) were cleaved off and desorbed, in agreement with previous studies [37]. After desorbing TMS groups, the alkyne groups start to form intermolecular five-membered rings with nearby pyrrole ring in porphyrin [38]. These units can further trigger coupling reaction to form chain or square shape conjugated structure (Fig. 1 and Supplementary Figs. 3 and 4). Figure 1g shows the high-resolution image of the 1b layer, which owns a linear fragment composed of a metal center and four porphyrin units. The 1b layer remains the monolayer configuration with a height of 0.18 ± 0.01 nm (Supplementary Fig. 3). The distance between two Cu centers in 1b monolayer is successfully decreased to 0.98 ± 0.03 nm, which is significantly closer than the 1.50 nm of 1a monolayer.

Different from TMS protected alkyne group, we also used another Cu-coordinated porphyrin molecule 5,10,15,20-tetrakis(4-bromophenyl)porphyrin (2a) and Ullmann coupling [39] to generate covalent porphyrin monolayer with longer inter-site distance between Cu centers (Fig. 2a). According to STM images, the vapor deposition of 2a on Au(111) substrate also led to the formation of large area of self-assembled molecules (Fig. 2b). The molecules appear a four-pointed star shape, and each point of the star is corresponding to the Br-phenyl group (Fig. 2c). The height of the assembled 2a molecular layer was measured as 0.28 ± 0.01 nm (Supplementary Fig. 5), and also reflect the flat adsorption and monolayer configuration. The distance between two Cu centers is 1.62 ± 0.03 nm (Fig. 2d). After annealing the self-assembly on Au(111) at 200°C for 30 mins, an Ullmann coupling of 2a via the selective activation of the terminal tran-position Br substituents occurred, bringing extended 2b molecular networks (Fig. 2e-f) [40]. 2b still maintains a monolayer structure after Ullmann coupling (Supplementary Fig. 6), but the distance between two Cu centers increases to 1.73 ± 0.03 nm (Fig. 2g).

Evaluation and comparison of CO ₂ RR activity. As displayed above, Cu-coordinated porphyrin monolayers with different inter-distance of Cu sites were successfully constructed on Au(111) substrate, which could be named as Cu098 (polymer 1b on Au(111)), Cu150 (self-assembly of 1a on Au(111)), Cu163 (self-assembly of 2a on Au(111)) and Cu174 (polymer 2b on Au(111)), respectively. The as-synthesized catalysts could be directly utilized as working electrode in electrolysis, due to the good mechanical strength and electrical conductivity of Au(111) substrate. The CO₂ electrocatalytic performance of all samples were conducted in a conventional H-type cell with 0.1 M KHCO₃ as electrolyte. The CO₂RR activity of four samples were estimated firstly via linear sweep voltammetry (LSV). As observed in Supplementary Fig. 7, Cu098, Cu150, Cu163, and Cu174 all show a significantly increasing geometrical current density in a CO₂ environment when compared with that in an N₂ environment, suggesting the domination of CO₂ reduction reaction rather than the parasitic hydrogen evolution reaction (HER). Nevertheless, the influence of Au(111) substrate must excluded since Au itself is also a widely-reported catalyst for CO₂RR. Hence, a pristine Au(111) substrate was also used as cathode to test the CO₂RR activity. The LSV currents of in CO₂ environment of gold is slightly higher than those of the four samples, possibly because organic molecules partially cover the surface of Au(111) [30]. The gas-phase and liquid-phase products were analysed using online gas chromatography (GC) and nuclear magnetic resonance spectroscopy (NMR). Except H₂, CO is the only detected product from CO₂RR procedure with a maximum faradaic efficiency (FE) of 22.3% (Supplementary Fig. 8). Therefore, Au(111) substrate would not contribute to the multicarbon products in CO₂ electrolysis, consistent with the former reports [26, 41].

To better trace the dynamic evolution of gaseous products, differential electrochemical mass spectrometry (DEMS) with a higher temporal resolution [42] was applied to probe the CO₂RR procedure on the Cu098, Cu150, Cu163 and Cu174 electrodes with a negatively going potential scan at 1 mV s^− 1 in CO₂-saturated 0.1 M KHCO₃ electrolyte. The faradaic currents on four samples and ionic currents detected by DEMS are displayed in Fig. 3 and Supplementary Fig. 9. As the potential passes − 0.5 V_RHE in the negative going scan, a reduction process is observed in faradaic currents of all the four samples. This is accompanied by the evolution of a signal in the ionic current for m/z = 2, indicating the HER procedure and formation of H₂. CO₂ starts to consume at ca. 0 V_RHE on all the catalysts, along with the synchronous increase of faradaic currents (Supplementary Fig. 9). DEMS measurements of Cu098, Cu150, Cu163 and Cu174 all exhibit a steady increase of CO (m/z = 28) yield in terms of ionic currents, indicating the similar activity for CO production. On the contrary, only Cu098 owns a steady increase of C₂H₄ yield in terms of ionic current (Fig. 3a, m/z = 26 for the fragment of C₂H₂⁺). Nothing other than a weak signal of C₂H₄ could be observed on Cu150, and no ionic currents of C₂H₄ are detected on Cu163 and Cu174 (Fig. 3b-d).

GC provides the quantitative analysis of reduction products from CO₂RR (Supplementary Fig. 10), which is highly coincide with the DEMS results on four samples. The combined product distribution and FEs of these catalysts are directly summarized in Fig. 4a-b. On one hand, four samples exhibit very similar trends of CO FEs within the applied potential range from − 0.4 V_RHE to − 1.4 V_RHE. Cu098, Cu150, Cu163 and Cu174 obtained the maximum CO FEs of 26.5%, 27.6%, 26.8% and 25.3%, respectively. On the other hand, the Cu098 catalyst exhibited an appreciable 6.1% FE of C₂H₄ at − 0.8 V _RHE (Fig. 4b), obviously superior to Cu150 with a maximum 1.2% FE of C₂H₄. For Cu163 and Cu174 catalysts, the FEs of C₂H₄ dropped dramatically to almost negligible levels. These DEMS and GC data directly demonstrate that the distance between Cu sites significantly determines the selectivity of multicarbon products in CO₂RR procedure. With a 0.895 nm inter-distance in former report [10] or 0.98 nm in our research, Cu atoms were close enough to each other to enhance the C − C coupling procedure, thus resulting in C₂H₄ as a main CO₂RR product. The C − C coupling pathway was suppressed to a great extent if enlarging the Cu inter-distance to 1.50 nm, and totally blocked when the inter-distance was increased to 1.63 nm and 1.74 nm, leading to the sharp decline of C₂H₄ production.

It is noteworthy to emphasize the importance of the monolayer distribution of our Cu-coordinated porphyrin molecules. Metalloporphyrin (MP) and metallophthalocyanine (MPc) are both typical model catalysts for M–N₄ active sites [27–29]. However, MP or MPc molecules could easily pile up or agglomerate into large particles due to the strong π-π stacking interaction [34]. Once the molecules are stacked together, it is unlikely to precisely control the distance between M–N₄ units. Consequently, contrast experiments were also conducted in this research. Monomeric 1a were dispersed in solution and loaded on the Au(111) substrate via a typical drop-casting method. According to scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) mapping images (Supplementary Fig. 11), 1a molecules agglomerate to form approximately 5 nm nanoparticles on Au(111) subtrate, although the 1a concentration in dispersed solutions is extremely low. Moreover, the CO₂RR activity of this drop-casted 1a catalyst was also evaluated in 0.1 M KHCO₃ electrolyte, and GC revealed the generation of C₂H₄, CH₄, CO, and H₂ (Supplementary Fig. 12). Specificlly, the C₂H₄ FEs of drop-casted 1a catalyst fully exceed those of 1a monolayer throughout the applied potential range, and reach a maximum of 9.6% at − 0.8 V _RHE. When 1a molecules agglomerate into nanoparticles, Cu sites are close enough to each other to produce C₂H₄, and it would be impossible to investigate the relationship between inter-distance and FEs of multicarbon products. On the contrary, Cu150 and Cu098 can maintain a monolayer distribution of 1a and 1b after the electrolysis, which is the prerequisite for comparing the impact of inter-site distance on the selectivity of CO₂RR products.

Theoretical calculation and mechanism research. To further confirm our proposed mechanism, density functional theory (DFT) calculations were performed to demonstrate the C₂H₄ selectivity of CO₂RR on different inter-distances of Cu sites. Notably, a typical single-atom system always builds the calculated models of M–N/O_X-C sites located in graphene with the fitted structure from XAFS data [26]. In our research, Accurate computational models could be constructed based on the 1a, 1b, 2a and 2b molecular structures (Supplementary Fig. 13–16 ). As reported in former research, the overall total reaction processes of C₂H₄ are formed in multiple reaction steps and 8e^– reductions with H₂O as the H⁺ source [23–24]. The formation of *COOH is the initial obstacle to the CO₂RR procedure and the potential determining step for CO production. The formation of the intermediate *COOH are all endothermic on four catalysts with close free energy barriers of 0.68 eV, 0.70 eV, 0.73 eV and 0.78 eV for Cu098, Cu150, Cu162, and Cu173, respectively. Subsequently, the *COOH intermediate on the active sites takes another electron and proton to form the *CO intermediate. Four model catalysts possess the identical Cu-N4 structure with similar coordination environment, which could explain the close free energy barriers in the initial steps.

To produce C₂H₄, two *CO species can couple directly to from *COCO, or a *CO is firstly hydrogenated into *COH and *COH will be coupe with a desorbed CO. In our model catalysts, the two adjacent *CO intermediates adsorbed on the Cu sites are separated by at least 0.98 nm, obviously not suitable for direct 2*CO→*COCO process [10]. Thus, the intermediate *CO should be furtherly hydrogenated into *COH, and the other *CO intermediate needs to be desorbed before the C − C dimerization. Finally, *CHO would be coupled with the desorbed CO by *CHO + CO→*CHOCO, which is the rate-limiting step (RLS) during the whole process [12–13]. Comparing to those of Cu098 (0.89 eV) and Cu150 (1.63 eV), the much larger free energies for C–C coupling step on Cu162 (1.81 eV) and Cu173 (1.92 eV) implies high-energy barriers for the CO₂-to-C₂H₄ process. In addition, the desorbed CO is difficult to continue coupling with *CHO due to the long distance between Cu centers, resulting in higher CO efficiency on Cu162 and Cu173. These calculation results are completely consistent with the experimental results, and directly demonstrate the crucial role of inter-site distance in the pathway of multi-carbon products in CO₂ electroreduction.

In conclusion, Cu-coordinated porphyrins with clear Cu–N4 active sites are constructed as monolayer structures on Au(111) substrate via self-assembly and on-surface polymerization strategy. The distance between Cu centers can be accurately controlled to 0.98 nm, 1.50 nm, 1.63 nm, and 1.74 nm by changing the length of organic ligands and the state of aggregation. According to DEMS and GC results, Cu atoms were close enough to each other to enhance the C − C coupling procedure and obtained an appreciable 6.1% FE of C₂H₄ with a 0.98 nm inter-distance. The C − C coupling pathway was largely suppressed if enlarging the Cu inter-distance to 1.50 nm, and totally blocked when the inter-distance was increased to 1.63 nm and 1.74 nm, leading to the sharp decline of C₂H₄ production. The theoretical evidences also reveal the decisive effect of the distance effect on the selectivity towards multi-carbon products. This work has considerable guiding significance for the design of high-performance electrocatalysts for CO₂ reduction.

Conflict of interest

The authors declare that they have no conflict of interest.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (U21A20312, 22172099, 22101181, and 21975162), Guangdong Basic and Applied Basic Research Foundation (2023A1515012776, 2022B1515120084), and the Guangdong Province “Pearl River Talents Plan” Innovative and Entrepreneurial Teams Project (2021ZT09C289 to X.L.). We also acknowledge the Instrumental Analysis Centre of Shenzhen University for performing TEM.

S. Nitopi, E. Bertheussen, S. B. Scott, X. Liu, A. K. Engstfeld, S. Horch, B. Seger, I. E. Stephens, K. Chan, C. Hahn, Progress and Perspectives of Electrochemical CO₂ Reduction on Copper in Aqueous Electrolyte, Chem. Rev. 119, 7610–7672 (2019).
Y. Y. Birdja, E. Pérez-Gallent, M. C. Figueiredo, A. J. Göttle, F. Calle-Vallejo, M. T. M. Koper, Advances and Challenges in Understanding the Electrocatalytic Conversion of Carbon Dioxide to Fuels. Nat. Energy 4, 732 – 745 (2019).
P. P. Yang, X. L. Zhang, P. Liu, D. J. Kelly, Z. Z. Niu, Y. Kong, L. Shi, Y. R. Zheng, M. H. Fan, H. J. Wang, M. R. Gao, Highly Enhanced Chloride Adsorption Mediates Efficient Neutral CO₂ Electroreduction over a Dual-Phase Copper Catalyst. J. Am. Chem. Soc. 145, 8714–8725 (2023).
M. Zhang, W. Wei, S. Zhou, D.-D. Ma, A. Cao, X.-T. Wu, Q.-L. Zhu, Engineering a Conductive Network of Atomically Thin Bismuthene With Rich Defects Enables CO₂ Reduction to Formate With Industry-Compatible Current Densities and Stability. Energy Environ. Sci. 14, 4998–5008 (2021).
D. Gao, R. M. Arán-Ais, H. S. Jeon, B. Cuenya, Rational Catalyst and Electrolyte Design for CO₂ Electroreduction towards Multicarbon Products. Nat. Catal. 2, 198–210 (2019).
T. T. H. Hoang, S. Verma, S. Ma, T. T. Fister, J. Timoshenko, A. I. Frenkel, P. J. A. Kenis, A. A. Gewirth, Nanoporous Copper-Silver Alloys by Additive-controlled Electrodeposition for the Selective Electroreduction of CO₂ to Ethylene and Ethanol. J. Am. Chem. Soc. 140, 5791–5797 (2018).
H. Luo, B. Li, J. G. Ma, P. Cheng, Surface Modification of nano-Cu₂O for Controlling CO₂ Electrochemical Reduction to Ethylene and Syngas. Angew. Chem., Int. Ed. 61, e202116736 (2022).
J. E. Huang, F. Li, A. Ozden, A. S. Rasouli, F. P. G. Arquer, S. Liu, S. Zhang, M. Luo, X. Wang, Y. Lum, Y. Xu, K. Bertens, R. K. Miao, C.-T. Dinh, D. Sinton, E. H. Sargent, CO₂ Electrolysis to Multicarbon Products in Strong Acid. Science 372, 1074–1078 (2021).
R. Yang, J. Duan, P. Dong, Q. Wen, M. Wu, Y. Liu, Y. Liu, H. Li, T. Zhai, In Situ Halogen-ion Leaching Regulates Multiple Sites on Tandem Catalysts for Efficient CO₂ Electroreduction to C2 + Products. Angew. Chem. Int. Ed. 61, e202116706 (2022).
Qiu, X.-F.; Zhu, H.-L.; Huang, J.-R.; Liao, P.-Q.; Chen, X.-M. Highly Selective CO₂ Electroreduction to C₂H₄ Using a Metal-Organic Framework with Dual Active Sites. J. Am. Chem. Soc. 143, 7242–7246 (2021).
T. Jiang, Y. Zhou, X. Ma, X. Qin, H. Li, C. Ding, B. Jiang, K. Jiang, W. Cai, Spectrometric Study of Electrochemical CO₂ Reduction on Pd and Pd–B Electrodes. ACS Catal. 11, 840–848 (2021).
Z.-Z. Wu, X.-L. Zhang, Z.-Z. Niu, F.-Y. Gao, P.-P. Yang, L.-P. Chi, L. Shi, W.-S. Wei, R. Liu, Z. Chen, S. Hu, X. Zheng, M.-R. Gao, Identification of Cu(100)/Cu(111) Interfaces as Superior Active Sites for CO Dimerization during CO₂ Electroreduction. J. Am. Chem. Soc. 144, 259–269 (2022).
P. De Luna, R. Quintero-Bermudez, C.-T. Dinh, M. B. Ross, O. S. Bushuyev, P. Todorović, T. Regier, S. O. Kelley, P. Yang, E. H. Sargent, Catalyst Electro-redeposition Controls Morphology and Oxidation State for Selective Carbon Dioxide Reduction. Nat. Catal. 1, 103–110 (2018).
Z. Tan, J. Zhang, Y. Yang, J. Zhong, Y. Zhao, J. Hu, B. Han, Z. Chen, Alkaline Ionic Liquid Microphase Promotes Deep Reduction of CO₂ on Copper. J. Am. Chem. Soc. 145, 21983–21990 (2023).
X. Jiang, X. Li, Y. Kong, C. Deng, X. Li, Q. Hu, H. Yang, C. He, Oxidation State Modulation of Bimetallic Tin-Copper Oxide Nanotubes for Selective CO₂ Electroreduction to Formate, Small 18, 2204148 (2022).
Y. Zhang, H. Jang, X. Ge, W. Zhang, Z. Li, L. Hou, L. Zhai, X. Wei, Z. Wang, M. G. Kim, S. Liu, Q. Qin, X. Liu, J. Cho, Single-atom Sn on Tensile-strained ZnO Nanosheets for Highly efficient Conversion of CO₂ into Formate. Adv. Energy Mater. 12, 2202695 (2022).
J. Gu, C. S. Hsu, L. Bai, H. M. Chen, X. L. Hu, Atomically Dispersed Fe³⁺ Sites Catalyze Efficient CO₂ Electroreduction to CO. Science 364, 1091–1094 (2019).
Y. Wang, J. Mao, X. Meng, L. Yu, D. Deng, X. Bao, Catalysis with Two-Dimensional Materials Confining Single Atoms: Concept, Design, and Applications. Chem. Rev. 119, 1806–1854 (2019).
Q. Chang, Y. Liu, J.-H. Lee, D. Ologunagba, S. Hwang, Z. Xie, S. Kattel, J. H. Lee, J. G. Chen, Metal-Coordinated Phthalocyanines as Platform Molecules for Understanding Isolated Metal Sites in the Electrochemical Reduction of CO₂. J. Am. Chem. Soc. 144, 16131–16138 (2022).
K. Yao, J. Li, H. Wang, R. Lu, X. Yang, M. Luo, N. Wang, Z. Wang, C. Liu, T. Jing, S. Chen, E. Cortes, S. A. Maier, S. Zhang, T. Li, Y. Yu, Y. Liu, X. Kang, H. Liang, Mechanistic Insights into OC-COH Coupling in CO₂ Electroreduction on Fragmented Copper. J. Am. Chem. Soc. 144, 14005–14011 (2022).
Y. Liang, J. Zhao, Y. Yang, S. F. Hung, J. Li, S. Zhang, Y. Zhao, A. Zhang, C. Wang, D. Appadoo, L. Zhang, Z. Geng, F. Li, J. Zeng, Stabilizing Copper Sites in Coordination Polymers toward Efficient Electrochemical C-C Coupling. Nat. Commun. 14, 474 (2023).
P. Wang, H. Yang, C. Tang, Y. Wu, Y. Zheng, T. Cheng, K. Davey, X. Huang, S. Z. Qiao, Boosting Electrocatalytic CO₂-toethanol Production via Asymmetric C – C Coupling. Nat. Commun. 13, 3754 (2022).
W. Li, L. Li, Q. Xia, S. Hong, L. Wang, Z. Yao, T.-S. Wu, Y.-L. Soo, H. Zhang, T. W. B. Lo, A. Robertson, W.; Liu, Q.; Hao, L.; Sun, Z. Lowering C – C Coupling Barriers for Efficient Electrochemical CO₂ Reduction to C₂H₄ by Jointly Engineering Single Bi Atoms and Oxygen Vacancies on CuO. Appl. Catal., B 318, 121823 (2022).
W. Ma, S. Xie, T. Liu, Q. Fan, J. Ye, F. Sun, Z. Jiang, Q. Zhang, J. Cheng,;Y. Wang, Electrocatalytic Reduction of CO₂ to Ethylene and Ethanol through Hydrogen-Assisted C-C Coupling over Fluorine-Modified Copper. Nat. Catal. 3, 478–487 (2020).
H. Yang, Y. Wu, G. Li, Q. Lin, Q. Hu, Q. Zhang, J. Liu, C. He, Scalable Production of Efficient Single-Atom Copper Decorated Carbon Membranes for CO₂ Electroreduction to Methanol, J. Am. Chem. Soc. 141, 12717 – 12723 (2019).
X. Su, X. F. Yang, Y. Huang, B. Liu, T. Zhang, Single-Atom Catalysis toward Efficient CO₂ Conversion to CO and Formate Products. Acc. Chem. Res. 52, 656–664 (2019).
Z. Liang, H.-Y. Wang, H. Zheng, W. Zhang, R. Cao, Porphyrin-Based Frameworks for Oxygen Electrocatalysis and Catalytic Reduction of Carbon Dioxide. Chem. Soc. Rev. 50, 2540–2581 (2021).
S. Ren, D. Joulié, D. Salvatore, K. Torbensen, M. Wang, M. Robert, C. P. Berlinguette, Molecular Electrocatalysts can Mediate Fast, Selective CO₂ Reduction in a Flow Cell. Science 365, 367–369 (2019).
J. Wang, S. Dou, X. Wang, Structural Tuning of Heterogeneous Molecular Catalysts for Electrochemical Energy Conversion. Sci. Adv. 7, eabf3989 (2021).
C. Costentin, S. Drouet, M. Robert, J. M. Savéant, A Local Proton Source Enhances CO₂ Electroreduction to CO by a Molecular Fe Catalyst. Science 338, 90–94 (2012).
Y.-R. Wang, M. Liu, G.-K. Gao, Y.-L. Yang, R.-X. Yang, H.-M. Ding, Y. Chen, S.-L. Li, Y.-Q. Lan, Implanting Numerous Hydrogen-Bonding Networks in a Cu-Porphyrin-Based Nanosheet to Boost CH₄ Selectivity in Neutral-Media CO₂ Electroreduction. Angew. Chem. Int. Ed. 60, 21952–21958 (2021).
Z. Jin, P. Li, Y. Meng, Z. Fang, D. Xiao, G. Yu, Understanding the Inter-Site Distance Effect in Single-Atom Catalysts for Oxygen Electroreduction. Nat. Catal. 4, 615–622 (2021).
D.-H. Nam, P. De Luna, A. Rosas-Hernández, A. Thevenon, F. Li, T. Agapie, J. C. Peters, O. Shekhah, M. Eddaoudi, E. H. Sargent, Molecular Enhancement of Heterogeneous CO₂ Reduction. Nat. Mater. 19, 266–276 (2020).
Y. Wang, X. Dan, X. Wang, Z. Yi, J. Fu, Y. Feng, J. Hu, D. Wang, L. Wan, Probing the Synergistic Effects of Mg²⁺ on CO₂ Reduction Reaction on CoPc by In Situ Electrochemical Scanning Tunneling Microscopy. J. Am. Chem. Soc. 144, 20126–20133 (2022).
X. Wang, Y. Wang, Y. Feng, D. Wang, L. Wan, Insights into Electrocatalysis by Scanning Tunnelling Microscopy. Chem. Soc. Rev. 50, 5832–5849 (2021).
Z. Chen, P. Gao, W. Wang, S. Klyatskaya, Z. Zhao-Karger, D. Wang, C. Kübel, O. Fuhr, M. Fichtner, M. Ruben, A Lithium-Free Energy-Storage Device Based on an Alkyne-Substituted-Porphyrin Complex. ChemSusChem 12, 3737 – 3741 (2019).
S. Mahapatra, J. F. Schultz, L. Li, X. Zhang, N. Jiang, Controlling Localized Plasmons via an Atomistic Approach: Attainment of Site-Selective Activation inside a Single Molecule. J. Am. Chem. Soc. 144, 2051–2055 (2022).
N. Cao, J. Björk, E. Corral-Rascon, Z. Chen, M. Ruben, M. O. Senge, J. V. Barth, A. Riss, The role of aromaticity in the cyclization and polymerization of alkyne-substituted porphyrins on Au(111). Nat. Chem. 15, 1765–1772 (2023).
L. Lafferentz, V. Eberhardt, C. Dri, C. Africh, G. Comelli, F. Esch, S. Hecht, L. Grill, Controlling On-Surface Polymerization by Hierarchical and Substrate-Directed Growth. Nat. Chem. 4, 215–220 (2012).
S. Gu, S. Fu, C. Gong, S. Li, X. Liu, Yan Lu, Z. Wang, L. Wang, Directing on-Surface Polymerization via a Substrate-directed Molecular Template. Phys. Chem. Chem. Phys. 24, 3030–3034 (2022).
X. Yuan, L. Zhang, L. Li, H. Dong, S. Chen, W. Zhu, C. Hu, W. Deng, Z. J. Zhao, J. Gong, Ultrathin Pd-Au Shells with Controllable Alloying Degree on Pd Nanocubes toward Carbon Dioxide Reduction. J. Am. Chem. Soc. 141, 4791–4794 (2019).
E. L. Clark, A. T. Bell, Direct Observation of the Local Reaction Environment during the Electrochemical Reduction of CO₂. J. Am. Chem. Soc. 140, 7012–7020 (2018).

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Constructing Monolayer Model Catalysts to Uncover the Distance Effect on CO₂ Electroreduction towards Multi-Carbon Products

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