界面调控对二氧化碳电还原催化剂性能的影响及其机理研究

电催化二氧化碳还原技术能够有效应对当前人类社会面临的温室效应与能源危机的双重挑战。在多种二氧化碳电催化剂中，金属铜具有独一无二的多碳产物选择性，能够提升二氧化碳还原产物的经济价值，因而受到广泛的关注。但在铜上发生的二氧化碳还原反应过程非常复杂，涉及到多个关键中间体和多条反应路径，导致其产物选择性不佳，限制了其工业化的价值。在多种调控策略中，金属-碳基界面材料具有很大开发潜力。在本文中，我们设计合成了两种具有特定官能团修饰的类石墨炔材料并将其包覆在铜纳米线表面，以实现对界面微环境的精确控制，从而改变其二氧化碳还原产物选择性。借助准原位和原位表征手段研究了修饰官能团-界面微环境-催化产物选择性三者之间的关联。具体研究内容如下：

1. 分别合成了具有强吸电子基团氟和强供电子基团甲基修饰的类石墨炔前体，通过原位聚合反应制备出由甲基修饰的类石墨炔包覆的铜纳米线材料Me-GDY@CuNW和由氟修饰的类石墨炔包覆的铜纳米线材料F-GDY@CuNW，从而在铜纳米线表面构筑出清晰、均匀的金属-碳基材料界面。通过对其电催化二氧化碳产物分布的研究，发现在-2 V的最佳还原电位下，F-GDY@CuNW生成乙烯和乙醇的法拉第效率分别达到40%和21%，是纯铜纳米线对应产物法拉第效率的2倍和5倍   ，而Me-GDY@CuNW则具有4倍于铜纳米线的甲烷法拉第效率，达到38%，实现对产物选择性的显著控制。
2. 借助准原位的形貌、价态表征技术，结合电化学原位拉曼光谱，对发生在Me-GDY@CuNW和F-GDY@CuNW表面的二氧化碳还原过程进行了分析。发现引入吸电子基团的界面使表面铜原子价态降低，而界面处的供电子基团则会略微提高表面铜原子的价态。这种价态的变化改变了反应过程中铜对中间体的结合能力，并最终导致了产物选择性的变化。

[1] 林泉. 发展煤化工所面临的CO2排放问题及其对策CO2 emission issue in developing coal chemical industry and preliminary discussion on the emission reduction methods[J]. 化学工业, 2007, 25(7): 17-20.
[2] 宋绍峰. 制冷工质的环保明星——二氧化碳[J]. 节能与环保, 2006, (10): 3.
[3] 代兴超, 王斌, 王爱勤, et al. Pd/PAL催化二氧化碳、氢气和胺反应合成甲酰胺Amine formylation with CO2 and H2 catalyzed by heterogeneous Pd/PAL catalyst[J]. 催化学报, 2019, 40(8): 1141-1146.
[4] 梁嘉欣, 叶淑娴, 王拴紧, et al. 二氧化碳共聚物的序列结构控制及其结构与性能的关系Sequence structure control of CO2-based copolymer and the relationship between structure and properties[J]. 科学通报, 2021, 66(7): 798-815.
[5] ALAM M I, CHEULA R, MORONI G, et al. Mechanistic and multiscale aspects of thermo-catalytic CO2 conversion to C1 products[J]. Catalysis Science & Technology, 2021, 11(20): 6601-6629.
[6] YAMAZAKI Y, TAKEDA H, ISHITANI O. Photocatalytic reduction of CO2 using metal complexes[J]. Journal of Photochemistry and Photobiology C-Photochemistry Reviews, 2015, 25: 106-137.
[7] ZHANG W H, MOHAMED A R, ONG W J. Z-Scheme photocatalytic systems for carbon dioxide reduction: Where are we now?[J]. Angewandte Chemie International Edition, 2020, 59(51): 22894-22915.
[8] ZHANG N, YANG B P, LIU K, et al. Machine learning in screening high performance electrocatalysts for CO2 reduction[J]. Small Methods, 2021, 5(11): 2100987.
[9] JUNEAU M, VONGLIS M, HARTVIGSEN J, et al. Assessing the viability of K-Mo2C for reverse water-gas shift scale-up: molecular to laboratory to pilot scale[J]. Energy & Environmental Science, 2020, 13(8): 2524-2539.
[10] ROSTRUP-NIELSEN J R, PEDERSEN K, SEHESTED J. High temperature methanation Sintering and structure sensitivity[J]. Applied Catalysis A: General, 2007, 330: 134-138.
[11] BEHRENS M, STUDT F, KASATKIN I, et al. The active site of methanol synthesis over Cu/ZnO/Al2O3 industrial catalysts[J]. Science, 2012, 336(6083): 893-897.
[12] VRIJBURG W L, GARBARINO G, CHEN W, et al. Ni-Mn catalysts on silica-modified alumina for CO2 methanation[J]. Journal of Catalysis, 2020, 382: 358-371.
[13] KORTLEVER R, PETERS I, KOPER S, et al. Electrochemical CO2 reduction to formic acid at low overpotential and with high Faradaic efficiency on carbon-supported bimetallic Pd-Pt nanoparticles[J]. ACS Catalysis, 2015, 5(7): 3916-3923.
[14] ARMSTRONG F A, HIRST J. Reversibility and efficiency in electrocatalytic energy conversion and lessons from enzymes[J]. Proceedings of the National Academy of Sciences of the United States of America, 2011, 108(34): 14049-14054.
[15] YOO J S, CHRISTENSEN R, VEGGE T, et al. Theoretical insight into the trends that guide the electrochemical reduction of carbon dioxide to formic acid[J]. Chemsuschem, 2016, 9(4): 358-363.
[16] SHEN J, KORTLEVER R, KAS R, et al. Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrin[J]. Nature Communications, 2015, 6(4): 809-815.
[17] SHEN J, KOLB M J, GOTTLE A J, et al. DFT study on the mechanism of the electrochemical reduction of CO2 catalyzed by cobalt porphyrins[J]. Journal of Physical Chemistry C, 2016, 120(29): 15714-15721.
[18] BAGGER A, JU W, VARELA A S, et al. Electrochemical CO2 reduction: A classification problem[J]. Chemphyschem, 2017, 18(22): 3266-3273.
[19] BUSHUYEV O S, DE LUNA P, DINH C T, et al. What should we make with CO2 and how can we make it?[J]. Joule, 2018, 2(5): 825-832.
[20] TORELLI D A, FRANCIS S A, CROMPTON J C, et al. Nickel-gallium-catalyzed electrochemical reduction of CO2 to highly reduced products at low overpotentials[J]. ACS Catalysis, 2016, 6(3): 2100-2104.
[21] CALVINHO K U D, LAURSEN A B, YAP K M K, et al. Selective CO2 reduction to C3 and C4 oxyhydrocarbons on nickel phosphides at overpotentials as low as 10 mV[J]. Energy & Environmental Science, 2018, 11(9): 2550-2559.
[22] HORI Y, MURATA A, TAKAHASHI R, et al. Electroreduction of carbon monoxide to methane and ethylene at a copper electrode in aqueous solutions at ambient temperature and pressure[J]. Journal of the American Chemical Society, 1987, 109(16): 5022-5023.
[23] HORI Y, TAKAHASHI R, YOSHINAMI Y, et al. Electrochemical reduction of CO at a copper electrode[J]. The Journal of Physical Chemistry B, 1997, 101(36): 7075-7081.
[24] LUO W J, NIE X W, JANIK M J, et al. Facet Dependence of CO2 reduction paths on Cu electrodes[J]. Acs Catalysis, 2016, 6(1): 219-229.
[25] NIE X W, ESOPI M R, JANIK M J, et al. Selectivity of CO2 reduction on copper electrodes: The role of the kinetics of elementary steps[J]. Angewandte Chemie International Edition, 2013, 52(9): 2459-2462.
[26] CHENG T, XIAO H, GODDARD W A. Full atomistic reaction mechanism with kinetics for CO reduction on Cu(100) from ab initio molecular dynamics free-energy calculations at 298 K[J]. Proceedings of the National Academy of Sciences of the United States of America, 2017, 114(8): 1795-1800.
[27] GOODPASTER J D, BELL A T, HEAD-GORDON M. Identification of possible pathways for C-C bond formation during electrochemical reduction of CO2: New theoretical insights from an improved electrochemical model[J]. Journal of Physical Chemistry Letters, 2016, 7(8): 1471-1477.
[28] HORI Y, TAKAHASHI I, KOGA O, et al. Selective formation of C2 compounds from electrochemical reduction of CO2 at a series of copper single crystal electrodes[J]. Journal of Physical Chemistry B, 2002, 106(1): 15-17.
[29] HAHN C, HATSUKADE T, KIM Y G, et al. Engineering Cu surfaces for the electrocatalytic conversion of CO2: Controlling selectivity toward oxygenates and hydrocarbons[J]. Proceedings of the National Academy of Sciences of the United States of America, 2017, 114(23): 5918-5923.
[30] WANG L, NITOPI S A, BERTHEUSSEN E, et al. Electrochemical Carbon Monoxide Reduction on Polycrystalline Copper: Effects of Potential, Pressure, and pH on Selectivity toward Multicarbon and Oxygenated Products [J]. Acs Catalysis, 2018, 8(8): 7445-7454.
[31] RESASCO J, CHEN L D, CLARK E, et al. Promoter effects of alkali metal cations on the electrochemical reduction of carbon dioxide[J]. Journal of the American Chemical Society, 2017, 139(32): 11277-11287.
[32] RESASCO J, LUM Y, CLARK E, et al. Effects of anion identity and concentration on electrochemical reduction of CO2[J]. Chemelectrochem, 2018, 5(7): 1064-1072.
[33] AHN S T, ABU-BAKER I, PALMORE G T R. Electroreduction of CO2 on polycrystalline copper: Effect of temperature on product selectivity[J]. Catalysis Today, 2017, 288: 24-29.
[34] LIU X Y, XIAO J P, PENG H J, et al. Understanding trends in electrochemical carbon dioxide reduction rates[J]. Nature Communications, 2017, 8: 15438-15444.
[35] WANG Z, YANG G, ZHANG Z, et al. Selectivity on etching: Creation of high-energy facets on copper nanocrystals for CO2 electrochemical reduction[J]. ACS Nano, 2016, 10(4): 4559-4564.
[36] MANDAL L, YANG K R, MOTAPOTHULA M R, et al. Investigating the role of copper oxide in electrochemical CO2 reduction in real time[J]. ACS Appled Mater Interfaces, 2018, 10(10): 8574-8584.
[37] MISTRY H, VARELA A S, BONIFACIO C S, et al. Highly selective plasma-activated copper catalysts for carbon dioxide reduction to ethylene[J]. Nature Communications, 2016, 7: 12123-12130.
[38] WANG X, WANG Z Y, DE ARQUER F P G, et al. Efficient electrically powered CO2-to-ethanol via suppression of deoxygenation[J]. Nature Energy, 2020, 5(6): 478-486.
[39] LI G X, LI Y L, LIU H B, et al. Architecture of graphdiyne nanoscale films[J]. Chemical Communications, 2010, 46(19): 3256-3258.
[40] FERREIRA R B, FIGUEROA J M, FAGNANI D E, et al. Benzotrifuran (BTFuran): a building block for pi-conjugated systems[J]. Chemical Communications, 2017, 53(69): 9590-9593.
[41] HENNRICH G, LYNCH V M, ANSLYN E V. Novel C3-symmetric molecular scaffolds with potential facial differentiation[J]. Chemistry-A European Journal, 2002, 8(10): 2274-2278.
[42] CHANG Y, LYE M L, ZENG H C. Large-scale synthesis of high-quality ultralong copper nanowires[J]. Langmuir, 2005, 21(9): 3746-3748.
[43] LI X D, WANG N, HE J J, et al. One-Step Preparation of highly durable superhydrophobic carbon nanothorn arrays[J]. Small, 2020, 16(26): 1907013.
[44] CLARK D T, MUSGRAVE W K, KILCAST D, et al. Applications of ESCA to polymer chemistry: Studies of some nitroso rubbers[J]. Journal of Polymer Science Part A-1: Polymer Chemistry, 1972, 10(6): 1637-1654.
[45] PLATZMAN I, BRENER R, HAICK H, et al. Oxidation of polycrystalline copper thin films at ambient conditions[J]. The Journal of Physical Chemistry C, 2008, 112(4): 1101-1108.
[46] DUBOT P, JOUSSET D, PINET V, et al. Simulation of the LMM auger spectra of copper[J]. Surface and Interface Analysis, 1988, 12(1-12): 99-104.
[47] BURDYNY T, SMITH W A. CO2 reduction on gas-diffusion rlectrodes and why catalytic performance must be assessed at commercially-relevant Conditions[J]. Energy & Environmental Science, 2019, 12(5): 1442-1453.
[48] GABARDO C M, SEIFITOKALDANI A, EDWARDS J P, et al. Combined high alkalinity and pressurization enable efficient CO2 electroreduction to CO[J]. Energy & Environmental Science, 2018, 11(9): 2531-2539.
[49] GABARDO C M, O'BRIEN C P, EDWARDS J P, et al. Continuous carbon dioxide electroreduction to concentrated multi-carbon products using a membrane electrode assembly[J]. Joule, 2019, 3(11): 2777-2791.
[50] LU X, LEUNG D Y C, WANG H Z, et al. A pH-differential dual-electrolyte microfluidic electrochemical cells for CO2 utilization[J]. Renewable Energy, 2016, 95: 277-285.
[51] O'HAYRE R, BARNETT D M, PRINZ F B. The triple phase boundary - A mathematical model and experimental investigations for fuel cells [J]. Journal of the Electrochemical Society, 2005, 152(2): A439-A444.
[52] MARINI S, SALVI P, NELLI P, et al. Advanced alkaline water electrolysis[J]. Electrochimica Acta, 2012, 82: 384-391.
[53] WENG L C, BELL A T, WEBER A Z. Modeling gas-diffusion electrodes for CO2 reduction[J]. Physical Chemistry Chemical Physics, 2018, 20(25): 16973-16984.
[54] LIN R, GUO J X, LI X J, et al. Electrochemical reactors for CO2 conversion[J]. Catalysts, 2020, 10(5).
[55] NITOPI S, BERTHEUSSEN E, SCOTT S B, et al. Progress and perspectives of electrochemical CO2 reduction on copper in aqueous electrolyte[J]. Chemical Reviews, 2019, 119(12): 7610-7672.
[56] RONG W F, ZOU H Y, ZANG W J, et al. Size-dependent activity and selectivity of atomic-level copper nanoclusters during CO/CO2 electroreduction [J]. Angewandte Chemie International Edition, 2021, 60(1): 466-472.
[57] JEANMAIRE D L, VANDUYNE R P. Surface Raman spectroelectrochemistry: Part 1. Heterocyclic, aromatic, and aliphatic amines adsorbed on the anodized silver electrode[J]. Journal of Electroanalytical Chemistry, 1977, 84(1): 1-20.
[58] LEUNG L W H, WEAVER M J. Extending the metal interface generality of surface-enhanced Raman spectroscopy: Underpotential deposited layers of mercury, thallium, and lead on gold electrodes[J]. Journal of Electroanalytical Chemistry, 1987, 217(2): 367-384.
[59] LI J F, HUANG Y F, DING Y, et al. Shell-isolated nanoparticle-enhanced Raman spectroscopy[J]. Nature, 2010, 464(7287): 392-395.
[60] YEO B S, KLAUS S L, ROSS P N, et al. Identification of hydroperoxy species as reaction intermediates in the electrochemical evolution of oxygen on gold[J]. Chemphyschem, 2010, 11(9): 1854-1857.
[61] YANG H, HU Y W, CHEN J J, et al. Intermediates adsorption engineering of CO2 electroreduction reaction in highly selective heterostructure Cu-based electrocatalysts for CO production[J]. Advanced Energy Materials, 2019, 9(27): 1901396.
[62] LU X, ZHU C Q, WU Z S, et al. In situ observation of the pH Gradient near the gas diffusion electrode of CO2 reduction in alkaline electrolyte[J]. Journal of the American Chemical Society, 2020, 142(36): 15438-15444.
[63] SCHOUTEN K J P, GALLENT E P, KOPER M T M. The influence of pH on the reduction of CO and CO2 to hydrocarbons on copper electrodes[J]. Journal of Electroanalytical Chemistry, 2014, 716: 53-57.
[64] BODAPPA N, SU M, ZHAO Y, et al. Early stages of electrochemical oxidation of Cu(111) and polycrystalline Cu surfaces revealed by in Situ Raman spectroscopy[J]. Journal of the American Chemical Society, 2019, 141(31): 12192-12196.
[65] ZHAO Y, CHANG X, MALKANI A S, et al. Speciation of Cu surfaces during the electrochemical CO reduction reaction[J]. Journal of the American Chemical Society, 2020, 142(21): 9735-9743.
[66] CHERNYSHOVA I V, SOMASUNDARAN P, PONNURANGAM S. On the origin of the elusive first intermediate of CO2 electroreduction[J]. Proceedings of the National Academy of Sciences of the United States of America, 2018, 115(40): E9261-E9270.
[67] DE LUNA P, QUINTERO-BERMUDEZ R, DINH C T, et al. Catalyst electro-redeposition controls morphology and oxidation state for selective carbon dioxide reduction[J]. Nature Catalysis, 2018, 1(2): 103-110.
[68] BAI X W, LI Q, SHI L, et al. Hybrid Cu0 and Cux+ as atomic interfaces promote high-selectivity conversion of CO2 to C2H5OH at low potential[J]. Small, 2020, 16(12): 1901981.