為因應近年來的能源危機、全球暖化和氣候變遷等挑戰，以電化學法將二氧化碳還原成可利用之化學產品以達到碳中和的目的，在近來吸引了廣大的關注。
二氧化碳可作為許多低碳燃料如甲酸、甲醇、乙醇等的原料，使之以高能量密度與可再生之形式將能量儲存。然而，大多數電化學還原法需使用貴金屬（鉑或鈀）作為電極，或需在極為高溫、高壓的條件下才可將二氧化碳還原，因此限制了其在工業應用的發展。在本研究中，使用奈米銅顆粒複合還原氧化石墨烯（rGO）作為電化學法之電極，該電極可於較低之工作電位進行二氧化碳之還原，研究中也同時比較了不同材料，如鉑、鈀、rGO和rGO / Cu等電極的還原效果，並利用氣相儀探討在不同酸鹼值下對還原電位及還原物產率之影響。
值得一提的是，該實驗方法可在溫和的環境(常溫常壓)下進行且不使用複雜的設備。與貴金屬電極（Pt和Pd）相比，rGO / Cu電極可大幅降低電極的成本。希冀該研究成果能為二氧化碳衍生低碳燃料鋪設一條新道路，並進一步促進電化學還原工藝之發展。

In response to challenges of energy crisis, global warming and climate change, electrochemical carbon dioxide reduction to produce chemicals or low-carbon fuels can serve as a means for carbon neutral and therefore has attracted much attention recently. The notorious greenhouse gas carbon dioxide can then become feedstock to synthesize numerous low-carbon fuels such as formate/formic acid, methanol, ethanol and others to provide renewable energy storage with high energy density forms.
However, most of electrochemical reduction processes utilize precious metals (platinum or palladium) as electrode, or apply harsh temperature/pressure conditions which may limit the development of electrochemical reduction of carbon dioxide toward industrial applications. In this thesis work, we use copper nanoparticle decorated reduced graphene oxide (rGO), which is derived from one of the most abundant elements (i.e. carbon), as the electrochemical reduction electrode. The process can achieve carbon dioxide reduction with lower working potential. Electrode materials of platinum, palladium, rGO and copper decorated rGO as working potential were compared. The influences of reduction potential, electrode material and electrolyte acidity on production yield were discussed and characterized by scanning electron microscopy and gas chromatography.
In addition, this process was conducted under ambient temperature/pressure without harsh condition or complicated equipments. The rGO/Cu electrode can achieve a cost reduction of 95% in average compared to precious metal electrodes (Pt and Pd). The work shall pave a new path toward developing carbon dioxide reduction electrodes and further promote development of electrochemical reduction process toward carbon dioxide derived low-carbon fuels.

Contents …………………………………………….. Ⅰ
Abstract ………..……………………………………. Ⅲ
中文摘要 …......................………….………...…….... Ⅳ

Chapter 1 Introduction 1
1-1 Nanotechnology 1
1-2 Introduction to Graphene 3
1-2.1 Overview 3
1-2.2 Graphene Production Techniques 5
1-3 Introduction to Carbon Dioxide Reduction 13
1-3.1 Overview 13
1-3.2 Utilization of Carbon Dioxide 16
1-3.3 Introduction of Formaldehyde 18
Chapter 2 Experimental Procedures 21
2-1 Electrode Preparation 21
2-1.1 Preparation of rGO Electrode 21
2-1.2 Copper Nanoparticle Deposition 22
2-2 Electrochemistry 23
2-2.1 Introduction to Cyclic Voltammetry (CV) 23
2-2.2 Experimental Process 24
2-3 Gas Chromatography 25
2-4 Scanning Electron Microscope Observation 27
2-5 Energy dispersive spectrometers (EDS) 28
Chapter 3 Results and Discussion 29
3-1 SEM Analysis of Microstructure and Morphology 29
3-2 Mechanism of Carbon Dioxide Reduction 32
3-3 CV Analysis and Reduction Reactions 34
3-4 Results of GC Analysis 37
Chapter 4 Summary and Conclusions 42
Chapter 5 Furture Prospects 44
References 46

References

[1] A. P. Alivisatos, "Semiconductor Clusters, Nanocrystals, and Quantum Dots," Science, vol. 271, pp. 933-937, 1996.
[2] M. Narihiro, G. Yusa, Y. Nakamura, T. Noda, and H. Sakaki, "Resonant Tunneling of Electrons via 20 nm Scale InAs Quantum Dot and Magnetotunneling Spectroscopy of Its Electronic States," Applied Physics Letters, vol. 70, pp. 105-107, 1997.
[3] J. Chen, M. A. Reed, A. M. Rawlett, and J. M. Tour, "Large On-Off Ratios and Negative Differential Resistance in A Molecular Electronic Device," Science, vol. 286, pp. 1550-1552, 1999.
[4] J. D. Meindl, Q. Chen, and J. A. Davis, "Limits on Silicon Nanoelectronics for Terascale Integration," Science, vol. 293, pp. 2044-2049, 2001.
[5] C. M. Lieber, "The Incredible Shrinking Circuit," Sci Am, vol. 285, pp. 58-64, 2001.
[6] V. Balzani, A. Credi, and M. Venturi, "The Bottom-Up Approach to Molecular-Level Devices and Machines," Chemistry – A European Journal, vol. 8, pp. 5524-5532, 2002.
[7] K. E. Drexler, Engines of Creation: Fourth Estate, 1996.
[8] K. E. Drexler, "Machine-phase Nanotechnology - A Molecular Nanotechnology Pioneer Predicts That the Tiniest Robots Will Revolutionize Manufacturing and Transform Society," Scientific American, vol. 285, pp. 74-75, 2001.
[9] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, et al., "Electric Field Effect in Atomically Thin Carbon Films," Science, vol. 306, pp. 666-669, 2004.
[10] A. K. Geim and K. S. Novoselov, "The Rise of Graphene," Nat Mater, vol. 6, pp. 183-191, 2007.
[11] Y. Zhu, S. Murali, M. D. Stoller, K. J. Ganesh, W. Cai, P. J. Ferreira, et al., "Carbon-Based Supercapacitors Produced by Activation of Graphene," Science, vol. 332, pp. 1537-1541, 2011.
[12] K. K. Lee, S. Deng, H. M. Fan, S. Mhaisalkar, H. R. Tan, E. S. Tok, et al., " α-Fe2O3 Nanotubes-reduced Graphene Oxide Composites as Synergistic Electrochemical Capacitor Materials," Nanoscale, vol. 4, pp. 2958-2961, 2012.
[13] C. T. J. Low, F. C. Walsh, M. H. Chakrabarti, M. A. Hashim, and M. A. Hussain, "Electrochemical Approaches to The Production of Graphene Flakes and Their Potential Applications," Carbon, vol. 54, pp. 1-21, 2013.
[14] K. S. Novoselov, V. I. Falko, L. Colombo, P. R. Gellert, M. G. Schwab, and K. Kim, "A Roadmap for Graphene," Nature, vol. 490, pp. 192-200, 10/11/print 2012.
[15] K. P. Loh, Q. Bao, P. K. Ang, and J. Yang, "The Chemistry of Graphene," Journal of Materials Chemistry, vol. 20, pp. 2277-2289, 2010.
[16] C. Berger, Z. Song, T. Li, X. Li, A. Y. Ogbazghi, R. Feng, et al., "Ultrathin Epitaxial Graphite:  2D Electron Gas Properties and A Route toward Graphene-based Nanoelectronics," The Journal of Physical Chemistry B, vol. 108, pp. 19912-19916, 2004.
[17] W. S. Hummers and R. E. Offeman, "Preparation of Graphitic Oxide," Journal of the American Chemical Society, vol. 80, pp. 1339-1339, 1958.
[18] B. C. Brodie, "On the Atomic Weight of Graphite," Philosophical Transactions of the Royal Society of London, vol. 149, pp. 249-259, 1859.
[19] L. Staudenmaier, "Verfahren zur Darstellung der Graphitsäure," Berichte der deutschen chemischen Gesellschaft, vol. 31, pp. 1481-1487, 1898.
[20] H. C. Schniepp, J.-L. Li, M. J. McAllister, H. Sai, M. Herrera-Alonso, D. H. Adamson, et al., "Functionalized Single Graphene Sheets Derived from Splitting Graphite Oxide," The Journal of Physical Chemistry B, vol. 110, pp. 8535-8539, 2006.
[21] K. P. Loh, Q. Bao, G. Eda, and M. Chhowalla, "Graphene Oxide as A Chemically Tunable Platform for Optical Applications," Nat Chem, vol. 2, pp. 1015-1024, 2010.
[22] H. He, J. Klinowski, M. Forster, and A. Lerf, "A New Structural Model for Graphite Oxide," Chemical Physics Letters, vol. 287, pp. 53-56, 1998.
[23] W. Gao, L. B. Alemany, L. Ci, and P. M. Ajayan, "New Insights into The Structure and Reduction of Graphite Oxide," Nat Chem, vol. 1, pp. 403-408, 2009.
[24] A. Bagri, C. Mattevi, M. Acik, Y. J. Chabal, M. Chhowalla, and V. B. Shenoy, "Structural Evolution During The Reduction of Chemically Derived Graphene Oxide," Nat Chem, vol. 2, pp. 581-587, 2010.
[25] K. Al-Shurman and H. Naseem, "CVD Graphene Growth Mechanism on Nickel Thin Films," in Proceedings of the 2014 COMSOL Conference in Boston, 2014.
[26] X. Li, W. Cai, L. Colombo, and R. S. Ruoff, "Evolution of Graphene Growth on Ni and Cu by Carbon Isotope Labeling," Nano Letters, vol. 9, pp. 4268-4272, 2009.
[27] D. H. Seo, S. Pineda, J. Fang, Y. Gozukara, S. Yick, A. Bendavid, et al., "Single-step Ambient-air Synthesis of Graphene from Renewable Precursors as Electrochemical Genosensor," vol. 8, pp. 14217-, 2017.
[28] D. Coumou and S. Rahmstorf, "A Decade of Weather Extremes," Nature Clim. Change, vol. 2, pp. 491-496, 2012.
[29] B. Metz, O. Davidson, H. C. de Coninck, M. Loos, and L.A. Meyer, "IPCC Special Report on Carbon Dioxide Capture and Storage," 2005.
[30] K. P. Kuhl, E. R. Cave, D. N. Abram, and T. F. Jaramillo, "New Insights into The Electrochemical Reduction of Carbon Dioxide on Metallic Copper Surfaces," Energy & Environmental Science, vol. 5, pp. 7050-7059, 2012.
[31] G. A. Olah, "Beyond Oil and Gas: The Methanol Economy," Angewandte Chemie International Edition, vol. 44, pp. 2636-2639, 2005.
[32] C. R. International. (06/15/2017). "World's Largest CO2 Methanol Plant." Available: http://www.cri.is/projects-1/2016/2/14/worlds-largest-co2-methanol-plant
[33] B. Magill. (05/31/2017, 06/17/2017). "First Commercial Carbon Capture Plant Is Going Live in Switzerland." Available: http://grist.org/article/first-commercial-carbon-capture-plant-is-going-live-in-switzerland/
[34] Climeworks. (06/17/2017). Available: http://www.climeworks.com/
[35] H. Arakawa, M. Aresta, J. N. Armor, M. A. Barteau, E. J. Beckman, A. T. Bell, et al., "Catalysis Research of Relevance to Carbon Management:  Progress, Challenges, and Opportunities," Chemical Reviews, vol. 101, pp. 953-996, 2001.
[36] J. Liebig, Annalen der Chemie und Pharmacie: C.F. Winter'sche, 1859.
[37] K. P. A. d. W. z. Berlin, Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin: Königliche Akademie der Wissenschaften, 1867.
[38] G. Reuss, W. Disteldorf, A. O. Gamer, and A. Hilt, "Formaldehyde," in Ullmann's Encyclopedia of Industrial Chemistry, ed: Wiley-VCH Verlag GmbH & Co. KGaA, 2000.
[39] N. I. C. N. a. A. S. (NICNAS). (05//01/2013, 04/10/2017). "Formaldehyde in Clothing and Textile." Available: https://www.nicnas.gov.au/chemical-information/factsheets/chemical-name/formaldehyde-in-clothing-and-textiles
[40] L. R. Axelsen, "Outlook for Formaldehyde and Impact on Methanol Demand," 33'rd Annual IHS Chemical World Methanol Conference, pp. 2015.
[41] Y. Hori, I. Takahashi, O. Koga, and N. Hoshi, "Selective Formation of C2 Compounds from Electrochemical Reduction of CO2 at A Series of Copper Single Crystal Electrodes," The Journal of Physical Chemistry B, vol. 106, pp. 15-17, 2002.
[42] M. Gattrell, N. Gupta, and A. Co, "A Review of The Aqueous Electrochemical Reduction of CO2 to Hydrocarbons at Copper," Journal of Electroanalytical Chemistry, vol. 594, pp. 1-19, 2006.
[43] D. C. Marcano, D. V. Kosynkin, J. M. Berlin, A. Sinitskii, Z. Sun, A. Slesarev, et al., "Improved Synthesis of Graphene Oxide," ACS Nano, vol. 4, pp. 4806-4814, 2010.
[44] Y. Song, R. Peng, D. K. Hensley, P. V. Bonnesen, L. Liang, Z. Wu, et al., "High-Selectivity Electrochemical Conversion of CO2 to Ethanol Using A Copper Nanoparticle/N-Doped Graphene Electrode," ChemistrySelect, vol. 1, pp. 6055-6061, 2016.
[45] Wikimedia Commons contributors. File:Cyclovoltammogram.jpg. Available: https://commons.wikimedia.org/w/index.php?title=File:Cyclovoltammogram.jpg&oldid=118585053
[46] G. Seshadri, C. Lin, and A. B. Bocarsly, "A New Homogeneous Electrocatalyst for The Reduction of Carbon Dioxide to Methanol at Low Overpotential," Journal of Electroanalytical Chemistry, vol. 372, pp. 145-150, 1994.
[47] A. J. Morris, R. T. McGibbon, and A. B. Bocarsly, "Electrocatalytic Carbon Dioxide Activation: The Rate-Determining Step of Pyridinium-Catalyzed CO2 Reduction," ChemSusChem, vol. 4, pp. 191-196, 2011.
[48] K. Keets, E. Barton Cole, A. J. Morris, N. Sivasankar, K. Teamey, P. S. Lakkaraju, et al., "Analysis of Pyridinium Catalyzed Electrochemical and Photoelectrochemical Reduction of CO2: Chemistry and Economic Impact," Indian Journal of Chemistry-Part A InorganicPhysical Theoretical and Analytical, vol. 51, pp. 1284-, 2012.
[49] E. Barton Cole, P. S. Lakkaraju, D. M. Rampulla, A. J. Morris, E. Abelev, and A. B. Bocarsly, "Using A One-Electron Shuttle for the Multielectron Reduction of CO2 to Methanol: Kinetic, Mechanistic, and Structural Insights," Journal of the American Chemical Society, vol. 132, pp. 11539-11551, 2010.
[50] E. E. Barton Cole, M. F. Baruch, R. P. L’Esperance, M. T. Kelly, P. S. Lakkaraju, E. L. Zeitler, et al., "Substituent Effects in the Pyridinium Catalyzed Reduction of CO2 to Methanol: Further Mechanistic Insights," Topics in Catalysis, vol. 58, pp. 15-22, 2015.
[51] M. Le, M. Ren, Z. Zhang, P. T. Sprunger, R. L. Kurtz, and J. C. Flake, "Electrochemical reduction of CO2 to CH3OH at copper oxide surfaces," Journal of the Electrochemical Society, vol. 158, pp. E45-E49, 2011.
[52] W. Hou, W. H. Hung, P. Pavaskar, A. Goeppert, M. Aykol, and S. B. Cronin,"Photocatalytic Conversion of CO2 to Hydrocarbon Fuels via Plasmon-Enhanced Absorption and Metallic Interband Transitions," ACS Catalysis, vol. 1, pp. 929-936, 2011.
[53] M. Zhang, J. Cheng, X. Xuan, J. Zhou, and K. Cen, "CO2 Synergistic Reduction in a Photoanode-Driven Photoelectrochemical Cell with a Pt-Modified TiO2 Nanotube Photoanode and a Pt Reduced Graphene Oxide Electrocathode," ACS Sustainable Chemistry & Engineering, vol. 4, pp. 6344-6354, 2016.
[54] J. Albo, M. Alvarez-Guerra, P. Castano, and A. Irabien, "Towards The Electrochemical Conversion of Carbon Dioxide into Methanol," Green Chemistry, vol. 17, pp. 2304-2324, 2015.