Smita Takawane, Masatoshi Miyamoto, Takumi Watanabe and Tomonori Ohba
{"title":"Pressure-dependent CO2 thermolysis on barium titanate nanocatalysts†","authors":"Smita Takawane, Masatoshi Miyamoto, Takumi Watanabe and Tomonori Ohba","doi":"10.1039/D4SU00253A","DOIUrl":null,"url":null,"abstract":"<p >Rising CO<small><sub>2</sub></small> levels pose a significant threat to global warming, extreme weather events, and ecosystem disruption. Mitigating these effects requires a reduction in CO<small><sub>2</sub></small> concentration using innovative technologies for CO<small><sub>2</sub></small> capture, storage, and utilization. Perovskite-type barium titanate nanocatalysts have the potential for high CO<small><sub>2</sub></small> conversion into valuable solid carbon products at low temperatures. In this study, we investigated the pressure-dependent CO<small><sub>2</sub></small> conversion activity of barium titanate nanocatalysts at 700 K. A key focus of this study is the impact of pressure on the interaction between CO<small><sub>2</sub></small> molecules and barium titanate nanocatalysts to evaluate the CO<small><sub>2</sub></small> conversion mechanism. The primary structures of the nanocatalysts remained unchanged after CO<small><sub>2</sub></small> thermolysis, whereas carbon was deposited on the nanocatalysts above 0.05 MPa. The reactant carbons after CO<small><sub>2</sub></small> conversion at various pressures between 0.01 and 1.0 MPa at 700 K were evaluated by temperature-programmed desorption in an O<small><sub>2</sub></small> atmosphere. The desorption peaks observed at approximately 500 K, 800–900 K, and 900–1300 K were the results of desorption of chemisorbed CO<small><sub>2</sub></small>, less- and high-crystalline graphitic carbons. Chemisorbed CO<small><sub>2</sub></small> and less-crystalline graphitic carbon were observed at 0.05 MPa. Highly crystalline graphitic carbons were observed on the nanocatalysts after CO<small><sub>2</sub></small> thermolysis at 0.1–1.0 MPa as well as chemisorbed CO<small><sub>2</sub></small>, although the amount of carbon at 1.0 MPa was smaller than the others. Therefore, the approach of CO<small><sub>2</sub></small> thermolysis at a low temperature of 700 K and 0.1–0.5 MPa is promising for producing valuable solid carbon products and mitigating the environmental impact of CO<small><sub>2</sub></small> emissions.</p>","PeriodicalId":74745,"journal":{"name":"RSC sustainability","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2024/su/d4su00253a?page=search","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"RSC sustainability","FirstCategoryId":"1085","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/su/d4su00253a","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Rising CO2 levels pose a significant threat to global warming, extreme weather events, and ecosystem disruption. Mitigating these effects requires a reduction in CO2 concentration using innovative technologies for CO2 capture, storage, and utilization. Perovskite-type barium titanate nanocatalysts have the potential for high CO2 conversion into valuable solid carbon products at low temperatures. In this study, we investigated the pressure-dependent CO2 conversion activity of barium titanate nanocatalysts at 700 K. A key focus of this study is the impact of pressure on the interaction between CO2 molecules and barium titanate nanocatalysts to evaluate the CO2 conversion mechanism. The primary structures of the nanocatalysts remained unchanged after CO2 thermolysis, whereas carbon was deposited on the nanocatalysts above 0.05 MPa. The reactant carbons after CO2 conversion at various pressures between 0.01 and 1.0 MPa at 700 K were evaluated by temperature-programmed desorption in an O2 atmosphere. The desorption peaks observed at approximately 500 K, 800–900 K, and 900–1300 K were the results of desorption of chemisorbed CO2, less- and high-crystalline graphitic carbons. Chemisorbed CO2 and less-crystalline graphitic carbon were observed at 0.05 MPa. Highly crystalline graphitic carbons were observed on the nanocatalysts after CO2 thermolysis at 0.1–1.0 MPa as well as chemisorbed CO2, although the amount of carbon at 1.0 MPa was smaller than the others. Therefore, the approach of CO2 thermolysis at a low temperature of 700 K and 0.1–0.5 MPa is promising for producing valuable solid carbon products and mitigating the environmental impact of CO2 emissions.