Kaisar Ahmad, Aasif Asharafbhai Dabbawala, Kyriaki Polychronopoulou, Dalaver Anjum, Marko Gacesa, Maguy Abi Jaoude
{"title":"金属间钯镓催化剂在常压下氢化二氧化碳合成甲醇的动力学启示","authors":"Kaisar Ahmad, Aasif Asharafbhai Dabbawala, Kyriaki Polychronopoulou, Dalaver Anjum, Marko Gacesa, Maguy Abi Jaoude","doi":"10.1002/gch2.202400159","DOIUrl":null,"url":null,"abstract":"<p>This study presents a single-site microkinetic model for methanol synthesis by CO<sub>2</sub> hydrogenation over intermetallic Pd<sub>2</sub>Ga/SiO<sub>2</sub>. A reaction path analysis (RPA) combining theoretical results and realistic catalyst surface reaction data is established to elucidate the reaction mechanism and kinetic models of CO<sub>2</sub> hydrogenation to methanol and CO. The RPA leads to the derivation of rate expressions for both reactions without presumptions about the most abundant reactive intermediate (MARI) and rate-determining step (rds). The formation of H<sub>2</sub>COOH* is found to be the rds (step 19) for methanol synthesis via the formate pathway, with CO<sub>2</sub> and H-atoms adsorbed on intermetallic sites as the MARIs. The derived kinetic model is corroborated with experimental data acquired under different reaction conditions, using a lab-scale fixed-bed reactor and Pd<sub>2</sub>Ga/SiO<sub>2</sub> nanoparticles prepared by incipient wetness impregnation. The excellent agreement between the experimental data and the kinetic model (<i>R</i><sup>2</sup> = 0.99) substantiates the proposed mechanism with an activation energy of 61.52 kJ mol<sup>-1</sup> for methanol synthesis. The reported catalyst exhibits high selectivity to methanol (96%) at 1 bar, 150 °C, and H<sub>2</sub>/CO<sub>2</sub> ratio of 3:1. These findings provide critical insights to optimize catalysts and processes targeting CO<sub>2</sub> hydrogenation at atmospheric pressure and low temperatures for on-demand energy production.</p>","PeriodicalId":12646,"journal":{"name":"Global Challenges","volume":"8 10","pages":""},"PeriodicalIF":4.4000,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/gch2.202400159","citationCount":"0","resultStr":"{\"title\":\"Kinetic Insights into Methanol Synthesis from CO2 Hydrogenation at Atmospheric Pressure over Intermetallic Pd2Ga Catalyst\",\"authors\":\"Kaisar Ahmad, Aasif Asharafbhai Dabbawala, Kyriaki Polychronopoulou, Dalaver Anjum, Marko Gacesa, Maguy Abi Jaoude\",\"doi\":\"10.1002/gch2.202400159\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>This study presents a single-site microkinetic model for methanol synthesis by CO<sub>2</sub> hydrogenation over intermetallic Pd<sub>2</sub>Ga/SiO<sub>2</sub>. 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The excellent agreement between the experimental data and the kinetic model (<i>R</i><sup>2</sup> = 0.99) substantiates the proposed mechanism with an activation energy of 61.52 kJ mol<sup>-1</sup> for methanol synthesis. The reported catalyst exhibits high selectivity to methanol (96%) at 1 bar, 150 °C, and H<sub>2</sub>/CO<sub>2</sub> ratio of 3:1. 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引用次数: 0
摘要
本研究提出了在金属间 Pd2Ga/SiO2 上通过 CO2 加氢合成甲醇的单位微动力学模型。结合理论结果和实际催化剂表面反应数据,建立了反应路径分析(RPA),以阐明 CO2 加氢生成甲醇和 CO 的反应机理和动力学模型。通过 RPA,可以推导出这两个反应的速率表达式,而无需假定最丰富的反应中间体(MARI)和速率决定步骤(rds)。发现 H2COOH* 的形成是通过甲酸途径合成甲醇的速率决定步骤(步骤 19),金属间位点上吸附的 CO2 和 H 原子为 MARI。利用实验室规模的固定床反应器和通过初湿浸渍法制备的 Pd2Ga/SiO2 纳米粒子,在不同反应条件下获得的实验数据证实了推导出的动力学模型。实验数据与动力学模型(R2 = 0.99)之间的极佳一致性证实了所提出的机制,即甲醇合成的活化能为 61.52 kJ mol-1。在 1 bar、150 °C 和 H2/CO2 比率为 3:1 的条件下,报告的催化剂对甲醇具有很高的选择性(96%)。这些发现为优化常压低温下二氧化碳加氢催化剂和工艺以按需生产能源提供了重要启示。
Kinetic Insights into Methanol Synthesis from CO2 Hydrogenation at Atmospheric Pressure over Intermetallic Pd2Ga Catalyst
This study presents a single-site microkinetic model for methanol synthesis by CO2 hydrogenation over intermetallic Pd2Ga/SiO2. A reaction path analysis (RPA) combining theoretical results and realistic catalyst surface reaction data is established to elucidate the reaction mechanism and kinetic models of CO2 hydrogenation to methanol and CO. The RPA leads to the derivation of rate expressions for both reactions without presumptions about the most abundant reactive intermediate (MARI) and rate-determining step (rds). The formation of H2COOH* is found to be the rds (step 19) for methanol synthesis via the formate pathway, with CO2 and H-atoms adsorbed on intermetallic sites as the MARIs. The derived kinetic model is corroborated with experimental data acquired under different reaction conditions, using a lab-scale fixed-bed reactor and Pd2Ga/SiO2 nanoparticles prepared by incipient wetness impregnation. The excellent agreement between the experimental data and the kinetic model (R2 = 0.99) substantiates the proposed mechanism with an activation energy of 61.52 kJ mol-1 for methanol synthesis. The reported catalyst exhibits high selectivity to methanol (96%) at 1 bar, 150 °C, and H2/CO2 ratio of 3:1. These findings provide critical insights to optimize catalysts and processes targeting CO2 hydrogenation at atmospheric pressure and low temperatures for on-demand energy production.