{"title":"通过掺杂锰提高 Ru/Anatase-TiO2 的低温 CO2 甲烷化活性：揭示二氧化碳解离的关键作用","authors":"Shaorong Deng, Zijian Qian, Chenji Zhu, Boxing Cheng, Xiaowei Wang, Xiuzhong Fang, Xianglan Xu* and Xiang Wang, ","doi":"10.1021/acscatal.4c0380110.1021/acscatal.4c03801","DOIUrl":null,"url":null,"abstract":"<p >A series of Ru/Ti<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>O<sub>2</sub> catalysts with varying Mn/(Ti + Mn) molar ratios (<i>x</i> = 0.10–0.25) were synthesized to investigate the CO<sub>2</sub> methanation mechanism on anatase TiO<sub>2</sub>-supported Ru catalysts (Ru/a-TiO<sub>2</sub>) and develop high-performance catalysts at low temperatures. Among these catalysts, the Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> exhibited the highest activity, achieving approximately 65% CO<sub>2</sub> conversion at 230 °C, which is markedly superior to the unmodified Ru/a-TiO<sub>2</sub> catalyst yielding only about 15% CO<sub>2</sub> conversion. The majority of Mn cations were incorporated into the lattice of a-TiO<sub>2</sub> as Mn<sup>3+</sup> cations, forming a solid solution structure in the Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> support. This modification resulted in a higher specific surface area, improved reducibility, and increased oxygen vacancy compared with pure a-TiO<sub>2</sub>. Consequently, Ru dispersion and electronic metal–support interactions were enhanced in Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> compared to those in Ru/a-TiO<sub>2</sub>. In-situ diffuse reflectance infrared Fourier transform spectroscopy combined with temperature-programmed surface reaction experiments revealed that CO<sub>2</sub> methanation predominantly proceeded via the CO* route on the Ru/a-TiO<sub>2</sub>. The CO<sub>2</sub> adsorption in the presence of decomposed H<sub>2</sub> led to dissociation to linear CO*, followed by CO methanation where CO<sub>2</sub> dissociation to CO* was identified as the rate-determining step (RDS). Mn cation doping induced the formation of oxygen vacancies, significantly enhancing CO<sub>2</sub> dissociation on Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub>, thereby shifting the RDS to CO methanation. This mechanism explains the superior activity of Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> at low temperatures for CO<sub>2</sub> methanation compared to the Ru/a-TiO<sub>2</sub>.</p>","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"14 21","pages":"16508–16521 16508–16521"},"PeriodicalIF":11.3000,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Boosting Low-Temperature CO2 Methanation Activity on Ru/Anatase-TiO2 Via Mn Doping: Revealing the Crucial Role of CO2 Dissociation\",\"authors\":\"Shaorong Deng, Zijian Qian, Chenji Zhu, Boxing Cheng, Xiaowei Wang, Xiuzhong Fang, Xianglan Xu* and Xiang Wang, \",\"doi\":\"10.1021/acscatal.4c0380110.1021/acscatal.4c03801\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >A series of Ru/Ti<sub>1–<i>x</i></sub>Mn<sub><i>x</i></sub>O<sub>2</sub> catalysts with varying Mn/(Ti + Mn) molar ratios (<i>x</i> = 0.10–0.25) were synthesized to investigate the CO<sub>2</sub> methanation mechanism on anatase TiO<sub>2</sub>-supported Ru catalysts (Ru/a-TiO<sub>2</sub>) and develop high-performance catalysts at low temperatures. Among these catalysts, the Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> exhibited the highest activity, achieving approximately 65% CO<sub>2</sub> conversion at 230 °C, which is markedly superior to the unmodified Ru/a-TiO<sub>2</sub> catalyst yielding only about 15% CO<sub>2</sub> conversion. The majority of Mn cations were incorporated into the lattice of a-TiO<sub>2</sub> as Mn<sup>3+</sup> cations, forming a solid solution structure in the Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> support. This modification resulted in a higher specific surface area, improved reducibility, and increased oxygen vacancy compared with pure a-TiO<sub>2</sub>. Consequently, Ru dispersion and electronic metal–support interactions were enhanced in Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> compared to those in Ru/a-TiO<sub>2</sub>. In-situ diffuse reflectance infrared Fourier transform spectroscopy combined with temperature-programmed surface reaction experiments revealed that CO<sub>2</sub> methanation predominantly proceeded via the CO* route on the Ru/a-TiO<sub>2</sub>. The CO<sub>2</sub> adsorption in the presence of decomposed H<sub>2</sub> led to dissociation to linear CO*, followed by CO methanation where CO<sub>2</sub> dissociation to CO* was identified as the rate-determining step (RDS). Mn cation doping induced the formation of oxygen vacancies, significantly enhancing CO<sub>2</sub> dissociation on Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub>, thereby shifting the RDS to CO methanation. This mechanism explains the superior activity of Ru/Ti<sub>0.8</sub>Mn<sub>0.2</sub>O<sub>2</sub> at low temperatures for CO<sub>2</sub> methanation compared to the Ru/a-TiO<sub>2</sub>.</p>\",\"PeriodicalId\":9,\"journal\":{\"name\":\"ACS Catalysis \",\"volume\":\"14 21\",\"pages\":\"16508–16521 16508–16521\"},\"PeriodicalIF\":11.3000,\"publicationDate\":\"2024-10-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ACS Catalysis \",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/acscatal.4c03801\",\"RegionNum\":1,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acscatal.4c03801","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
摘要
为了研究锐钛型二氧化钛支撑的 Ru 催化剂（Ru/a-TiO2）的二氧化碳甲烷化机制，并开发低温下的高性能催化剂，我们合成了一系列具有不同 Mn/（Ti + Mn）摩尔比（x = 0.10-0.25）的 Ru/Ti1-xMnxO2 催化剂。在这些催化剂中，Ru/Ti0.8Mn0.2O2 表现出最高的活性，在 230 °C 时可实现约 65% 的 CO2 转化率，明显优于未改性 Ru/a-TiO2 催化剂仅产生约 15% 的 CO2 转化率。大部分 Mn 阳离子以 Mn3+ 阳离子的形式加入到 a-TiO2 的晶格中，在 Ti0.8Mn0.2O2 载体中形成固溶体结构。与纯 a-TiO2 相比，这种改性提高了比表面积，改善了还原性，增加了氧空位。因此，与 Ru/a-TiO2 相比，Ru/Ti0.8Mn0.2O2 中的 Ru 分散和电子金属-支撑相互作用得到了增强。原位漫反射红外傅立叶变换光谱结合温度编程表面反应实验表明，Ru/a-TiO2 上的 CO2 甲烷化主要通过 CO* 途径进行。在分解的 H2 存在下吸附的 CO2 会解离成线性 CO*，然后进行 CO 甲烷化，其中 CO2 解离成 CO* 被确定为速率决定步骤 (RDS)。锰阳离子掺杂诱导了氧空位的形成，显著增强了 Ru/Ti0.8Mn0.2O2 上的 CO2 解离，从而将 RDS 转变为 CO 甲烷化。与 Ru/a-TiO2 相比，Ru/Ti0.8Mn0.2O2 在低温下进行 CO2 甲烷化时具有更高的活性。
Boosting Low-Temperature CO2 Methanation Activity on Ru/Anatase-TiO2 Via Mn Doping: Revealing the Crucial Role of CO2 Dissociation
A series of Ru/Ti1–xMnxO2 catalysts with varying Mn/(Ti + Mn) molar ratios (x = 0.10–0.25) were synthesized to investigate the CO2 methanation mechanism on anatase TiO2-supported Ru catalysts (Ru/a-TiO2) and develop high-performance catalysts at low temperatures. Among these catalysts, the Ru/Ti0.8Mn0.2O2 exhibited the highest activity, achieving approximately 65% CO2 conversion at 230 °C, which is markedly superior to the unmodified Ru/a-TiO2 catalyst yielding only about 15% CO2 conversion. The majority of Mn cations were incorporated into the lattice of a-TiO2 as Mn3+ cations, forming a solid solution structure in the Ti0.8Mn0.2O2 support. This modification resulted in a higher specific surface area, improved reducibility, and increased oxygen vacancy compared with pure a-TiO2. Consequently, Ru dispersion and electronic metal–support interactions were enhanced in Ru/Ti0.8Mn0.2O2 compared to those in Ru/a-TiO2. In-situ diffuse reflectance infrared Fourier transform spectroscopy combined with temperature-programmed surface reaction experiments revealed that CO2 methanation predominantly proceeded via the CO* route on the Ru/a-TiO2. The CO2 adsorption in the presence of decomposed H2 led to dissociation to linear CO*, followed by CO methanation where CO2 dissociation to CO* was identified as the rate-determining step (RDS). Mn cation doping induced the formation of oxygen vacancies, significantly enhancing CO2 dissociation on Ru/Ti0.8Mn0.2O2, thereby shifting the RDS to CO methanation. This mechanism explains the superior activity of Ru/Ti0.8Mn0.2O2 at low temperatures for CO2 methanation compared to the Ru/a-TiO2.
期刊介绍：
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.
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