隨著全世界環保意識抬頭，人們越來越投入對於溫室氣體中的主成分二氧化碳的生成問題。除了減碳之外，另一主要發展是二氧化碳再利用技術，而目前二氧化碳再利用的應用有兩個方向，分別是碳捕捉與儲存後使用以及碳捕捉後直接反應再利用。本研究以二氧化碳的再利用為主軸，選用碳捕捉後直接反應再利用的方式。研究中我們探討二氧化碳與甲烷乾式重組反應以製備合成氣，以及二氧化碳氫化反應以製備甲醇等兩種途徑來進行二氧化碳再利用，以期能透過有效的反應設計後減緩全球暖化，並同時能利用排放的二氧化碳來生產具有經濟效益的產品。
延續先前之成果，在第一部分的研究工作中，我們以氣溶膠合成概念製備Ni-Ce-O混成式多孔奈米粒子作為觸媒，運用二氧化碳與甲烷乾式重組反應為二氧化碳再利用反應途徑製備合成氣，並且在反應中結合相對少量氧氣以提升操作穩定性。合成Ni-Ce-O混成式多孔奈米粒子是藉氣相蒸發誘導自組裝並以聚乙二醇作為軟模板，在前驅物自組裝時聚乙二醇在氣相熱分解，在其中形成中孔與微孔的結構。由結果顯示，在氣相合成中添加聚乙二醇作軟模板，會增加Ni-Ce-O混成式奈米結構中的比表面積及活性金屬表面積，並提高對二氧化碳與甲烷乾式重組反應的催化活性。而少量氧氣可協助移除反應中所形成的積碳，也可藉進行甲烷部分氧化反應以調控產物中氫氣與一氧化碳之比例。這項工作開發了一種氣相合成的混成式奈米多孔結構，可用於催化結合式反應(二氧化碳-甲烷重組反應及甲烷部分氧化反應)，達到產物中氫氣與一氧化碳比例之可控性，以提高二氧化碳再利用之應用層面。
在第二部分的研究工作中，我們持續探討使用結合式二氧化碳與甲烷之乾式重組反應。在觸媒材料的優化上，我們延續以氣溶膠合成法製備觸媒，以鎳、鈀及鈰的前驅物搭配商用二氧化矽奈米粉末作為載體以合成奈米粒子團簇。在反應製程的優化上，我們於二氧化碳與甲烷乾式重組反應中，結合相對少量水蒸氣以提升操作穩定性。此方法同樣以氣相蒸發誘導自組裝的過程，將鎳、鈀及鈰的前驅物自組裝在二氧化矽表面及孔洞之中，以製備出NiPdCeOx@SiO2混成式奈米粒子團簇。由結果顯示，添加二氧化矽能提高觸媒活性金屬之分散度創造出較小的NiOx晶徑，而含有鈀的觸媒能降低反應起始溫度及提高觸媒對反應的催化能力與材料穩定性。除此之外，水蒸氣的添加不但有助移除積碳的功用，還可進行甲烷蒸氣重組反應以調控產物中氫氣與一氧化碳之比例，是本研究中對二氧化碳再利用之反應的另一大優點。這項工作開發了一種混成式奈米粒子團簇以提高結合式反應(二氧化碳-甲烷重組反應及甲烷蒸氣重組反應)的催化活性，達到產物中氫氣與一氧化碳比例可控性，也提供了另一結合式反應之途徑來進行二氧化碳再利用。
在本研究中之第三部分工作，我們開發混成式奈米結構粒子作為觸媒材料，並採用二氧化碳氫化反應之途徑製備出甲醇 (註：液體、易於儲存的產物) 作為二氧化碳再利用之途徑。觸媒材料的製備方法上，我們以3-氨基丙基三乙氧基矽烷(APTES) 對商用氧化鋁奈米粉末作表面改質後，將其分散在水中形成膠體溶液，接著將銅及鋅的前驅物溶液擔載於氧化鋁上，經由高溫鍛燒再以氫氣選擇性還原氧化銅成為金屬態，最終形成Cu-ZnO@Al2O3混成式奈米結構。由結果顯示，氧化鋁的添加能提高金屬銅及氧化鋅的分散性，進而提高觸媒對二氧化碳氫化反應的催化效果(二氧化碳之轉化率及甲醇之選擇率均有提升)，並提升以金屬銅-氧化鋅為基底觸媒之鹼性位。此外，以APTES進行表面改質之氧化鋁的添加，也能大幅提高混成式奈米結構中的活性金屬表面積。由活性測試之結果看來，Cu-ZnO@Al2O3混成式奈米結構對二氧化碳氫化反應之催化表現與活性金屬表面積成正相關。對甲醇選擇性最佳(47-49 %)的觸媒為氧化鋁重量百分比在35-36 %之觸媒，也是擁有最多中鹼性位之觸媒。以製備之Cu-ZnO@Al2O3混成式奈米結構所達到最高甲醇產量為12989 ± 2007 μmol*g-1*h-1。此研究工作透過結合載體的膠體穩定性及可控之活性金屬與助劑的共沉澱，設計出製備混成式奈米結構的有效途徑，而此混成式奈米結構有效催化二氧化碳氫化反應，進而發展二氧化碳再利用之新途徑。
本研究運用新型材料製備技術開發出高效能混成式奈米結構，作為催化二氧化碳再利用反應之觸媒，這些高效能混成式奈米結構觸媒擁有非常良好的材料性質及催化活性，不但可以提升二氧化碳再利用反應之催化表現，並藉由結合反應原理來開發其應用性，達到提供二氧化碳再利用反應新興途徑之目標。

CO2 emission is an arising environmental issue (i.e., greenhouse effect) to date, and the reduction of CO2 emitted to the atmosphere is important from the prospect of environmental protection. On the other hand, utilization of the CO2 has shown a great interest to the advances of the technology, as it enables the conversion of the greenhouse gas (CO2) into valuable products. Nowadays, two directions for the developments of carbon dioxide utilization: (1) carbon capture and storage, and (2) carbon capture and utilization. This study focuses on the utilization of carbon dioxide by a simultaneous capture and conversion of CO2 to the valuable products by design: (1) the reforming of carbon dioxide with methane to produce syngas and (2) the hydrogenation of carbon dioxide to methanol.
In the first part of the work, we continue on development of Ni-Ce-O hybrid nanoporous particle as the catalyst using the aerosol-based synthesis for the reforming of CO2 with methane for the syngas production. The method combines the principles of aerosol-phase evaporation-induced aggregation of polyethylene glycol (PEG) as soft template in the sprayed aqueous droplets followed by a direct gas-phase thermal decomposition of the self-assembled precursor crystallites for the creation of mesopores in the hybrid nanostructure. The addition of oxygen not only effectively reduces the amount of coke deposition, but also accomplishs a tunability of H2/CO ratio. The results show the increases of specific surface area, pore volume and metal surface area in the Ni-Ce-O hybrid nanostructure by using the PEG template during the gas-phase synthesis. A high catalytic activity in term of turnover frequency of methane (0.93 s-1 at 600 °C) achieves. The work demonstrates a facile route for gas-phase synthesis of hybrid nanoporous catalyst useful for an effective CO2 utilization with ability in the tuning of the ratio of H2/CO to accomplish high selectivity for syngas production.
In the second part of the work, we demonstrate a facile aerosol-based approach to fabricate hybrid nanostrcutures, NiPdOx-CeO2 nanoparticles decorated on the SiO2 nanoparticle clusters, for the catalysis of steam-promoted CO2 reforming with methane. Ultrafine crystallites of active metal and promoter (≈5 nm) are created with tunable cluster sizes and chemical compositions. A superior catalytic performance achieves at a relatively low temperature (550 °C): remarkable turnover frequency of methane (≈2 s-1), tunable H2/CO ratio (1.1-1.9) and good operation stability over 100 hours. Incorporation of SiO2 nanoparticle cluster as support material increases dispersion of active metals and suppresses metal sintering during material synthesis and catalysis. Hybridization with Pd significantly improves the activity of Ni-based catalyst especially ≤600 °C. Addition of steam suppresses the coke formation by > 10 times. The work demonstrates a prototype study of developing bimetallic hybrid nanocatalysts homogeneously dispersed with promoter on the NPC mesoporous support by design, showing promise for the syngas production via synergistic catalysis of the combined CO2-methane reforming.
In the third part of the work, a facile sol-gel approach is demonstrated for the fabrication of Cu-ZnO-based hybrid nanostructures for the catalytic CO2 hydrogenation to methanol. The method combines colloid stabilization of Al2O3 nanoparticles (as support material) and controlled co-precipitation of Cu (active metal) and ZnO (promoter) onto the Al2O3 nanoparticles. The results show a successful synthesis of ultrafine Cu-ZnO nanocrystallites deposited on the Al2O3 nanoparticle clusters (Cu-ZnO@Al2O3). Hybridization with Al2O3 nanoparticles enhance metal dispersion and number of basic sites of the Cu-ZnO-based nanocatalyst. Aminosilane-based surface functionalization on the Al2O3 nanoparticle increases metal surface area in the hybrid nanostructure. The CO2 conversion catalyzed by the synthesized Cu-ZnO@Al2O3 is shown to be proportional to active surface area of the hybrid nanostructure. An optimum selectivity of the synthesized catalyst is identified (47-49 %) when the mass fraction of Al2O3 is 35-36 %, in correspondence to the highest moderate basicity of the synthesized hybrid nanostructures. The highest yield of methanol achieves 12989 ± 2007 μmol*g-1*h-1 by the developed Cu-ZnO@Al2O3. Our work demonstrates a prototype study of fabricating high-performance hybrid nanocatalyst with the support of mechanistic understanding in material synthesis for the synergistic catalysis of CO2 hydrogenation to methanol.
In summary, we demonstrate a comprehensive study on the synthesis of hybrid nanostructure, in combination with the principle of chemical reaction engineering, for the catalysis of CO2-based reactions. The developments of the hybrid nanostructure catalysts show promise for the carbon dioxide utilization.

[1] Kuch D. Fixing climate change through carbon capture and storage: Situating industrial risk cultures. Futures 2017;92:90-9.
[2] Ussiri D-A, Lal R. Carbon capture and storage in geologic formations. Carbon sequestration for climate change mitigation and adaptation. Springer; 2017:497-545.
[3] Notz R, Tönnies I, McCann N, Scheffknecht G, Hasse H. CO2 capture for fossil fuel-fired power plants. Chemical Engineering and Technology 2011;34(2):163-72.
[4] Alper E, Orhan O-Y. CO2 utilization: Developments in conversion processes. Petroleum 2017;3(1):109-26.
[5] Nam S-S, Kim H, Kishan G, Choi M-J, Lee K-W. Catalytic conversion of carbon dioxide into hydrocarbons over iron supported on alkali ion-exchanged Y-zeolite catalysts. Applied Catalysis A: General 1999;179(1-2):155-63.
[6] Inui T, Kitagawa K, Takeguchi T, Hagiwara T, Makino Y. Hydrogenation of carbon dioxide to C1-C7 hydrocarbons via methanol on composite catalysts. Applied Catalysis A: General 1993;94(1):31-44.
[7] Arena F, Mezzatesta G, Spadaro L, Trunfio G. Latest advances in the catalytic hydrogenation of carbon dioxide to methanol/dimethylether. Transformation and utilization of carbon dioxide. Springer; 2014:103-30.
[8] Tidona B, Koppold C, Bansode A, Urakawa A, von Rohr P-R. CO2 hydrogenation to methanol at pressures up to 950 bar. The Journal of Supercritical Fluids 2013;78:70-7.
[9] Bansode A, Urakawa A. Towards full one-pass conversion of carbon dioxide to methanol and methanol-derived products. Journal of Catalysis 2014;309:66-70.
[10] Aresta M. Carbon dioxide as chemical feedstock. John Wiley and Sons; 2010;55-88.
[11] Pakhare D, Spivey J. A review of dry (CO2) reforming of methane over noble metal catalysts. Chemical Society Reviews 2014;43(22):7813-37.
[12] Papadopoulou C, Matralis H, Verykios X. Utilization of biogas as a renewable carbon source: dry reforming of methane. Catalysis for alternative energy generation. Springer; 2012:57-127.
[13] Rostrupnielsen J, Hansen J-B. CO2-reforming of methane over transition metals. Journal of Catalysis 1993;144(1):38-49.
[14] Rostrup-Nielsen J-R, Sehested J, Nørskov J-K. Hydrogen and synthesis gas by steam-and CO2 reforming.Advances in Catalysis;2002,47:65-139.
[15] Bradford M-C, Vannice M-A. Catalytic reforming of methane with carbon dioxide over nickel catalysts I. Catalyst characterization and activity. Applied Catalysis A: General 1996;142(1):73-96.
[16] Liang T-Y, Low P-Y, Lin Y-S, Tsai D-H. Spherical porous nanoclusters of NiO and CeO2 nanoparticles as catalysts for syngas production. ACS Applied Nano Materials 2020;3(9):9035-45.
[17] Lin Y-S, Tu J-Y, Tsai D-H. Steam-promoted methane-CO2 reforming by NiPdCeOx@SiO2 nanoparticle clusters for syngas production. International Journal of Hydrogen Energy 2021;46(49):25103-13.
[18] Choudhary V-R, Mondal K-C. CO2 reforming of methane combined with steam reforming or partial oxidation of methane to syngas over NdCoO3 perovskite-type mixed metal-oxide catalyst. Applied Energy 2006;83(9):1024-32.
[19] Wei Q, Gao X, Liu G, Yang R, Zhang H, Yang G, et al. Facile one-step synthesis of mesoporous Ni-Mg-Al catalyst for syngas production using coupled methane reforming process. Fuel 2018;211:1-10.
[20] Siang T, Jalil A, Hamid M, Abdulrasheed A, Abdullah T, Vo D-V. Role of oxygen vacancies in dendritic fibrous M/KCC-1 (M= Ru, Pd, Rh) catalysts for methane partial oxidation to H2-rich syngas production. Fuel 2020;278:118360.
[21] Mosayebi A, Nasabi M. Steam methane reforming on LaNiO3 perovskite-type oxide for syngas production, activity tests and kinetic modeling. International Journal of Energy Research 2020;44(7):5500-15.
[22] Shakouri M, Hu Y, Lehoux R, Wang H. CO2 conversion through combined steam and CO2 reforming of methane reactions over Ni and Co catalysts. The Canadian Journal of Chemical Engineering 2020;99(1):153-65.
[23] Mosinska M, Szynkowska M-I, Mierczynski P. Oxy-steam reforming of natural gas on Ni catalysts—A minireview. Catalysts 2020;10(8):896.
[24] Kim C, Kim Y. Promotional effect of iron on nickel-based catalyst for combined steam-carbon dioxide reformation of methane. Journal of Nanoscience and Nanotechnology 2020;20(9):5506-9.
[25] Holladay J-D, Hu J, King D-L, Wang Y. An overview of hydrogen production technologies. Catalysis Today 2009;139(4):244-60.
[26] Ghaffari Saeidabad N, Noh Y-S, Alizadeh Eslami A, Song H-T, Kim H-D, Fazeli A, et al. A review on catalysts development for steam reforming of biodiesel derived glycerol; promoters and supports. Catalysts 2020;10(8):910.
[27] Kourtelesis M, Kousi K, Kondarides D-I. CO2 hydrogenation to methanol over La2O3-promoted CuO/ZnO/Al2O3 catalysts: A kinetic and mechanistic study. Catalysts 2020;10(2):183.
[28] Li S, Guo L, Ishihara T. Hydrogenation of CO2 to methanol over Cu/AlCeO catalyst. Catalysis Today 2020;339:352-61.
[29] Sun Y, Huang C, Chen L, Zhang Y, Fu M, Wu J, et al. Active site structure study of Cu/Plate ZnO model catalysts for CO2 hydrogenation to methanol under the real reaction conditions. Journal of CO2 Utilization 2020;37:55-64.
[30] Zhong J, Yang X, Wu Z, Liang B, Huang Y, Zhang T. State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanol. Chemical Society Reviews 2020;49(5):1385-413.
[31] Nguyen-Hoang T-T, Lin Y-S, Le T-N-H, Le T-K, Huynh T-K-X, Tsai D-H. Cu-ZnO@Al2O3 hybrid nanoparticle with enhanced activity for catalytic CO2 conversion to methanol. Advanced Powder Technology 2021;32(5):1785-92.
[32] Singh R, Dhir A, Mohapatra S-K, Mahla S-K. Dry reforming of methane using various catalysts in the process. Biomass Conversion and Biorefinery 2020;10(2):567-87.
[33] Anil C, Modak J-M, Madras G. Syngas production via CO2 reforming of methane over noble metal (Ru, Pt, and Pd) doped LaAlO3 perovskite catalyst. Molecular Catalysis 2020;484:110805.
[34] Whang H-S, Choi M-S, Lim J, Kim C, Heo I, Chang T-S, et al. Enhanced activity and durability of Ru catalyst dispersed on zirconia for dry reforming of methane. Catalysis Today 2017;293:122-8.
[35] Wang L, Hu R, Liu H, Wei Q, Gong D, Mo L, et al. Encapsulated Ni@ La2O3/SiO2 catalyst with a one-pot method for the dry reforming of methane. Catalysts 2020;10(1):38.
[36] Liang T-Y, Chen H-H, Tsai D-H. Nickel hybrid nanoparticle decorating on alumina nanoparticle cluster for synergistic catalysis of methane dry reforming. Fuel Process Technology 2020;201:106335.
[37] Li Z, Wang Z, Jiang B, Kawi S. Sintering resistant Ni nanoparticles exclusively confined within SiO2 nanotubes for CH4 dry reforming. Catalysis Science and Technology 2018;8(13):3363-71.
[38] Dixon R-A, Egdell R-G. Direct observation of sintering in a model oxide supported metal catalyst STM of Pd on WO3 (001). Journal of the Chemical Society, Faraday Transactions 1998;94(9):1329-31.
[39] Ma B, Bu S, Yuan Q, Zhao C. One-pot synthesis of highly sintering-and coking-resistant Ni nanoparticles encapsulated in dendritic mesoporous SiO₂ for methane dry reforming. 2018;54(99)13993-6.
[40] Li Z, Wang Z, Kawi S. Sintering and coke resistant core/yolk shell catalyst for hydrocarbon reforming. ChemCatChem 2019;11(1):202-24.
[41] Lu M, Zhang X, Deng J, Kuboon S, Faungnawakij K, Xiao S, et al. Coking-resistant dry reforming of methane over BN-nanoceria interface-confined Ni catalysts. Catalysis Science and Technology 2020;10:4237-44.
[42] Zhang Z, Sun Y, Wang Y, Sun K, Gao Z, Xu Q, et al. Steam reforming of acetic acid and guaiacol over Ni/Attapulgite catalyst: Tailoring pore structure of the catalyst with KOH activation for enhancing the resistivity towards coking. Molecular Catalysis 2020;493:111051.
[43] da S-Q Menezes J-P, Dias A-P-d-S, da Silva M-A, Souza M-M. Effect of alkaline earth oxides on nickel catalysts supported over γ-alumina for butanol steam reforming: Coke formation and deactivation process. International Journal of Hydrogen Energy 2020;45(43):22906-20.
[44] Liang T-Y, Lin C-Y, Chou F-C, Wang M, Tsai D-H. Gas-phase synthesis of Ni-CeOx hybrid nanoparticles and their synergistic catalysis for simultaneous reforming of methane and carbon dioxide to syngas. The Journal of Physical Chemistry C 2018;122(22):11789-98.
[45] Jung D-S, Park S-B, Kang Y-C. Design of particles by spray pyrolysis and recent progress in its application. Korean Journal of Chemical Engineering 2010;27(6):1621-45.
[46] Peterson A-K, Morgan D-G, Skrabalak S-E. Aerosol synthesis of porous particles using simple salts as a pore template. Langmuir 2010;26(11):8804-9.
[47] Chang H, Jang H-D. Controlled synthesis of porous particles via aerosol processing and their applications. Advanced Powder Technology 2014;25(1):32-42.
[48] Ay H, Üner D. Dry reforming of methane over CeO2 supported Ni, Co and Ni-Co catalysts. Applied Catalysis B: Environmental 2015;179:128-38.
[49] Chen C, Wang X, Huang H, Zou X, Gu F, Su F, et al. Synthesis of mesoporous Ni-La-Si mixed oxides for CO2 reforming of CH4 with a high H2 selectivity. Fuel Process Technology 2019;185:56-67.
[50] Das S, Ashok J, Bian Z, Dewangan N, Wai M, Du Y, et al. Silica-ceria sandwiched Ni core-shell catalyst for low temperature dry reforming of biogas: Coke resistance and mechanistic insights. Applied Catalysis B: Environmental 2018;230:220-36.
[51] Gonzalez-Delacruz V-M, Pereniguez R, Ternero F, Holgado J-P, Caballero A. Modifying the size of nickel metallic particles by H2/CO treatment in Ni/ZrO2 methane dry reforming catalysts. ACS Catalysis 2011;1(2):82-8.
[52] Gould T-D, Izar A, Weimer A-W, Falconer J-L, Medlin J-W. Stabilizing Ni catalysts by molecular layer deposition for harsh, dry reforming conditions. ACS Catalysis 2014;4(8):2714-7.
[53] Khzouz M, Wood J, Pollet B, Bujalski W. Characterization and activity test of commercial Ni/Al2O3, Cu/ZnO/Al2O3 and prepared Ni-Cu/Al2O3 catalysts for hydrogen production from methane and methanol fuels. International Journal of Hydrogen Energy 2013;38(3):1664-75.
[54] Li Z, Kathiraser Y, Ashok J, Oemar U, Kawi S. Simultaneous tuning porosity and basicity of nickel@nickel-magnesium phyllosilicate core-shell catalysts for CO2 reforming of CH4. Langmuir 2014;30(48):14694-705.
[55] Arbag H, Tasdemir H-M, Yagizatli Y, Kucuker M, Yasyerli S. Effect of preparation technique on the performance of Ni and Ce incorporated modified alumina catalysts in CO2 reforming of methane. Catalysis Letters 2020:1-13.
[56] Chuayboon S, Abanades S, Rodat S. High-purity and clean syngas and hydrogen production from two-step CH4 reforming and H2O splitting through isothermal ceria redox cycle using concentrated sunlight. Frontiers in Energy Research 2020;8:128.
[57] Padi S-P, Shelly L, Komarala E-P, Schweke D, Hayun S, Rosen B-A. Coke-free methane dry reforming over nano-sized NiO-CeO2 solid solution after exsolution. Catalysis Communications 2020;138:105951.
[58] Taira K, Sugiyama T, Einaga H, Nakao K, Suzuki K. Promoting effect of 2000 ppm H2S on the dry reforming reaction of CH4 over pure CeO2, and in situ observation of the behavior of sulfur during the reaction. Journal of Catalysis 2020;389:611-22.
[59] Warren K-J, Carrillo R-J, Greek B, Hill C-M, Scheffe J-R. Solar reactor demonstration of efficient and selective syngas production via chemical-looping dry reforming of methane over ceria. Energy Technology 2020:2000053.
[60] Batebi D, Abedini R, Mosayebi A. Combined steam and CO2 reforming of methane (CSCRM) over Ni-Pd/Al2O3 catalyst for syngas formation. International Journal of Hydrogen Energy 2020;45(28):14293-310.
[61] Charisiou N-D, Siakavelas G-I, Papageridis K-N, Motta D, Dimitratos N, Sebastian V, et al. The effect of noble metal (M: Ir, Pt, Pd) on M/Ce2O3-γ-Al2O3 catalysts for hydrogen production via the steam reforming of glycerol. Catalysts 2020;10(7):790.
[62] Zhu Y, Chen K, Yi C, Mitra S, Barat R. Dry reforming of methane over palladium-platinum on carbon nanotube catalyst. Chemical Engineering Communications 2018;205(7):888-96.
[63] Pan C, Guo Z, Dai H, Ren R, Chu W. Anti-sintering mesoporous Ni-Pd bimetallic catalysts for hydrogen production via dry reforming of methane. International Journal of Hydrogen Energy 2020;45(32):16133-43.
[64] Okada S, Manabe R, Inagaki R, Ogo S, Sekine Y. Methane dissociative adsorption in catalytic steam reforming of methane over Pd/CeO2 in an electric field. Catalysis Today 2018;307:272-6.
[65] Didenko L, Sementsova L, Chizhov P, Dorofeeva Т. Pure hydrogen production by steam reforming of methane mixtures with various propane contents in a membrane reactor with the industrial nickel catalyst and a Pd-Ru alloy foil. International Journal of Hydrogen Energy 2019;44(48):26396-404.
[66] Bian Z, Das S, Wai M-H, Hongmanorom P, Kawi S. A review on bimetallic nickel-based catalysts for CO2 reforming of methane. ChemPhysChem 2017;18(22):3117-34.
[67] De S, Zhang J, Luque R, Yan N. Ni-based bimetallic heterogeneous catalysts for energy and environmental applications. Energy and Environmental Science 2016;9(11):3314-47.
[68] Ren H-P, Tian S-P, Ding S-Y, Huang G-Q, Zhu M, Ma Q, et al. Carbon dioxide reforming of methane over Ni Supported SiO2: Influence of the preparation method on the resulting structural properties and catalytic activity. Catalysts 2020;10(7):795.
[69] Wang G, Liang Y, Song J, Li H, Zhao Y. Study on high activity and outstanding stability of hollow-NiPt@SiO2 core-shell structure catalyst for DRM reaction. Frontiers in Chemistry 2020;8:220.
[70] Wang C, Jie X, Qiu Y, Zhao Y, Al-Megren H-A, Alshihri S, et al. The importance of inner cavity space within Ni@SiO2 nanocapsule catalysts for excellent coking resistance in the high-space-velocity dry reforming of methane. Applied Catalysis B: Environmental 2019;259:118019.
[71] Lin C-Y, Chou F-C, Tsai D-H. Mechanistic understanding of surface reduction of CuCeO hybrid nanoparticles for catalytic methane combustion. Journal of the Taiwan Institute of Chemical Engineers 2018;92:80-90.
[72] Pati R-K, Lee I-C, Hou S, Akhuemonkhan O, Gaskell K-J, Wang Q, et al. Flame synthesis of nanosized Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O catalysts for the water-gas shift (WGS) reaction. ACS Applied Materials and Interfaces 2009;1(11):2624-35.
[73] Du X, Zhang D, Shi L, Gao R, Zhang J. Morphology dependence of catalytic properties of Ni/CeO2 nanostructures for carbon dioxide reforming of methane. The Journal of Physical Chemistry C 2012;116(18):10009-16.
[74] Jalal A, Uzun A. An exceptional selectivity for partial hydrogenation on a supported nickel catalyst coated with [BMIM][BF4]. Journal of Catalysis 2017;350:86-96.
[75] Pal P, Singha R-K, Saha A, Bal R, Panda A-B. Defect-induced efficient partial oxidation of methane over nonstoichiometric Ni/CeO2 nanocrystals. The Journal of Physical Chemistry C 2015;119(24):13610-8.
[76] Ashok J, Kawi S. Steam reforming of toluene as a biomass tar model compound over CeO2 promoted Ni/CaO-Al2O3 catalytic systems. International Journal of Hydrogen Energy 2013;38(32):13938-49.
[77] Al-Swai B-M, Osman N, Alnarabiji M-S, Adesina A-A, Abdullah B. Syngas production via methane dry reforming over ceria-magnesia mixed oxide-supported nickel catalysts. Industrial and Engineering Chemistry Research 2018;58(2):539-52.
[78] Ashok J, Ang M, Kawi S. Enhanced activity of CO2 methanation over Ni/CeO2-ZrO2 catalysts: Influence of preparation methods. Catalysis Today 2017;281:304-11.
[79] Ashok J, Das S, Dewangan N, Kawi S. H2S and NOx tolerance capability of CeO2 doped La1-xCexCo0.5Ti0.5O3-δ perovskites for steam reforming of biomass tar model reaction. Energy Conversion and Management: X 2019;1:100003.
[80] Singha R, Shukla A, Sandupatla A, Deo G, Bal R. Synthesis and catalytic activity of a Pd doped Ni-MgO catalyst for dry reforming of methane. Journal of Materials Chemistry A 2017;5(30):15688-99.
[81] Zhang L, Wang F, Zhu J, Han B, Fan W, Zhao L, et al. CO2 reforming with methane reaction over Ni@SiO2 catalysts coupled by size effect and metal-support interaction. Fuel 2019;256:115954.
[82] Han B, Zhao L, Wang F, Xu L, Yu H, Cui Y, et al. Effect of calcination temperature on the performance of the Ni@SiO2 catalyst in methane dry reforming. Industrial and Engineering Chemistry Research 2020;59(30):13370-9.
[83] Wang F, Han K, Xu L, Yu H, Shi W. Ni/SiO2 catalyst prepared by strong electrostatic adsorption for a low-temperature methane dry reforming reaction. Industrial and Engineering Chemistry Research 2021;60(8):3324-33.
[84] Wang J, Fu Y, Kong W, Jin F, Bai J, Zhang J, et al. Design of a carbon-resistant Ni@S-2 reforming catalyst: Controllable Ni nanoparticles sandwiched in a peasecod-like structure. Applied Catalysis B: Environmental 2021;282:119546.
[85] Theofanidis S-A, Galvita V-V, Poelman H, Marin G-B. Enhanced carbon-resistant dry reforming Fe-Ni catalyst: Role of Fe. ACS Catalysis 2015;5(5):3028-39.
[86] Jeon J, Nam S, Ko C-H. Rapid evaluation of coke resistance in catalysts for methane reforming using low steam-to-carbon ratio. Catalysis Today 2018;309:140-6.
[87] Wang N, Shen K, Huang L, Yu X, Qian W, Chu W. Facile route for synthesizing ordered mesoporous Ni-Ce-Al oxide materials and their catalytic performance for methane dry reforming to hydrogen and syngas. ACS Catalysis 2013;3(7):1638-51.
[88] Zhang Q, Tang T, Wang J, Sun M, Wang H, Sun H, et al. Facile template-free synthesis of Ni-SiO2 catalyst with excellent sintering-and coking-resistance for dry reforming of methane. Catalysis Communications 2019;131:105782.
[89] Xiao J, Mao D, Guo X, Yu J. Effect of TiO2, ZrO2, and TiO2-ZrO2 on the performance of CuO-ZnO catalyst for CO2 hydrogenation to methanol. Applied Surface Science 2015;338:146-53.
[90] Chen D, Mao D, Xiao J, Guo X, Yu J. CO2 hydrogenation to methanol over CuO-ZnO-TiO2-ZrO2: a comparison of catalysts prepared by sol-gel, solid-state reaction and solution-combustion. Journal of Sol-Gel Science and Technology 2018;86(3):719-30.
[91] Chen D, Mao D, Wang G, Guo X, Yu J. CO2 hydrogenation to methanol over CuO-ZnO-ZrO2 catalyst prepared by polymeric precursor method. Journal of Sol-Gel Science and Technology 2019;89(3):686-99.
[92] Lei H, Hou Z, Xie J. Hydrogenation of CO2 to CH3OH over CuO/ZnO/Al2O3 catalysts prepared via a solvent-free routine. Fuel 2016;164:191-8.
[93] Cai W, de la Piscina P-R, Toyir J, Homs N. CO2 hydrogenation to methanol over CuZnGa catalysts prepared using microwave-assisted methods. Catalysis Today 2015;242:193-9.
[94] Tian S, Yan F, Zhang Z, Jiang J. Calcium-looping reforming of methane realizes in situ CO2 utilization with improved energy efficiency. Science Advances 2019;5(4):5077.
[95] Ashok J, Kathiraser Y, Ang M, Kawi S. Bi-functional hydrotalcite-derived NiO-CaO-Al¬2O3 catalysts for steam reforming of biomass and/or tar model compound at low steam-to-carbon conditions. Applied Catalysis B: Environmental 2015;172:116-28.
[96] Di Lauro F, Tregambi C, Montagnaro F, Salatino P, Chirone R, Solimene R. Improving the performance of calcium looping for solar thermochemical energy storage and CO2 capture. Fuel 2021;298:120791.
[97] Bailera M, Pascual S, Lisbona P, Romeo L-M. Modelling calcium looping at industrial scale for energy storage in concentrating solar power plants. Energy 2021;225:120306.
[98] Daza Y-A, Kuhn J-N. CO2 conversion by reverse water gas shift catalysis: comparison of catalysts, mechanisms and their consequences for CO2 conversion to liquid fuels. RSC Advances 2016;6(55):49675-91.
[99] Ronda-Lloret M, Rico-Francés S, Sepúlveda-Escribano A, Ramos-Fernandez E-V. CuOx/CeO2 catalyst derived from metal organic framework for reverse water-gas shift reaction. Applied Catalysis A: General 2018;562:28-36.
[100] Zhou Y, Chen A, Ning J, Shen W. Electronic and geometric structure of the copper-ceria interface on Cu/CeO2 catalysts. Chinese Journal of Catalysis 2020;41(6):928-37.
[101] Shen W-J, Ichihashi Y, Matsumura Y. Low temperature methanol synthesis from carbon monoxide and hydrogen over ceria supported copper catalyst. Applied Catalysis A: General 2005;282(1-2):221-6.
[102] Zhu J, Su Y, Chai J, Muravev V, Kosinov N, Hensen EJ. Mechanism and nature of active sites for methanol synthesis from CO/CO2 on Cu/CeO2. ACS Catalysis 2020;10(19):11532-44.
[103] van de Water L-G, Wilkinson S-K, Smith R-A, Watson M-J. Understanding methanol synthesis from CO/H2 feeds over Cu/CeO2 catalysts. Journal of Catalysis 2018;364:57-68.