Pub Date : 2021-12-22DOI: 10.26434/chemrxiv-2021-x6q87
Kori Sye, Clare A Leahy, Josh Vura-Weis
Bridged μ-oxo iron bisporphyrins serve as photocatalysts for oxidative organic transformations, but suffer from low quantum efficiency. We use femtosecond optical and M2,3-edge XANES spectroscopy to investigate the early photodynamics of the μ-oxo iron bisporphyrin, (TPPFe)2O, providing evidence for the preferential formation of an TPPFe(III)+/TPPFe(III)-O- ion pair state instead of the desired TPPFe(II)/TPPFe(IV)=O.
{"title":"Low quantum efficiency of μ-oxo iron bisporphyrin photoacatalysts explained with femtosecond M-edge XANES","authors":"Kori Sye, Clare A Leahy, Josh Vura-Weis","doi":"10.26434/chemrxiv-2021-x6q87","DOIUrl":"https://doi.org/10.26434/chemrxiv-2021-x6q87","url":null,"abstract":"Bridged μ-oxo iron bisporphyrins serve as photocatalysts for oxidative organic transformations, but suffer from low quantum efficiency. We use femtosecond optical and M2,3-edge XANES spectroscopy to investigate the early photodynamics of the μ-oxo iron bisporphyrin, (TPPFe)2O, providing evidence for the preferential formation of an TPPFe(III)+/TPPFe(III)-O- ion pair state instead of the desired TPPFe(II)/TPPFe(IV)=O.","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84589712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-10-01DOI: 10.33774/chemrxiv-2021-hljbh
A. Pashkova, Bastien O. Burek, J. Bloh
Novel processes for the sustainable production of fertilizers are highly sought after to combat climate change. Herein, we demonstrate that by irradiating with strong UVA-light, TiO2 is able to photocatalytically oxidize molecular nitrogen in the gas phase under ambient conditions to NOx and nitrate. The reaction produces predominantly nitrogen dioxide with a high selectivity of up to 93% which could be captured afterwards to produce nitric acid or nitrates and used as sustainable (solar) fertilizer.
{"title":"Sustainable nitrate production out of thin air: The photocatalytic oxidation of molecular nitrogen","authors":"A. Pashkova, Bastien O. Burek, J. Bloh","doi":"10.33774/chemrxiv-2021-hljbh","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-hljbh","url":null,"abstract":"Novel processes for the sustainable production of fertilizers are highly sought after to combat climate change. Herein, we demonstrate that by irradiating with strong UVA-light, TiO2 is able to photocatalytically oxidize molecular nitrogen in the gas phase under ambient conditions to NOx and nitrate. The reaction produces predominantly nitrogen dioxide with a high selectivity of up to 93% which could be captured afterwards to produce nitric acid or nitrates and used as sustainable (solar) fertilizer.","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88507901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-30DOI: 10.33774/chemrxiv-2021-2w10h
Frederik Søndergaard‐Pedersen, R. Tilley, J. J. Gooding, Tania M. Benedetti, Munkhshur Myekhlai, B. Iversen, E. Bøjesen, Harish Lakhotiya, Martin Bondesgaard
Developing alternatives to platinum-based electrocatalysts for the hydrogen evolution reaction (HER) is an important challenge for realizing the green transition. This is especially the case for alkaline conditions where Pt-based catalysts have very poor stability. Here, we demonstrate new solvothermal synthesis methods with facile allotropism control for selectively obtaining hexagonal-close-packed (hcp) and face-centered cubic (fcc) ruthenium nanoparticles. Both samples are highly active HER catalysts in alkaline conditions outperforming commercial Pt/C. However, the samples show markedly different stabilities. The hcp sample shows exceptional stability for 12 hours constant operation at 10 mA/cm2 with an overpotential that only increases 6 mV whereas the fcc sample increases 50 mV and the commercial Pt/C more than 350 mV. Thus, this study underlines the importance of controlling the crystal structure of nanoparticle electrocatalysts and shows the potential of using Ru as an alternative to Pt in alkaline conditions.
{"title":"Highly efficient and stable Ru nanoparticle electrocatalyst for the hydrogen evolution reaction in alkaline conditions","authors":"Frederik Søndergaard‐Pedersen, R. Tilley, J. J. Gooding, Tania M. Benedetti, Munkhshur Myekhlai, B. Iversen, E. Bøjesen, Harish Lakhotiya, Martin Bondesgaard","doi":"10.33774/chemrxiv-2021-2w10h","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-2w10h","url":null,"abstract":"Developing alternatives to platinum-based electrocatalysts for the hydrogen evolution reaction (HER) is an important challenge for realizing the green transition. This is especially the case for alkaline conditions where Pt-based catalysts have very poor stability. Here, we demonstrate new solvothermal synthesis methods with facile allotropism control for selectively obtaining hexagonal-close-packed (hcp) and face-centered cubic (fcc) ruthenium nanoparticles. Both samples are highly active HER catalysts in alkaline conditions outperforming commercial Pt/C. However, the samples show markedly different stabilities. The hcp sample shows exceptional stability for 12 hours constant operation at 10 mA/cm2 with an overpotential that only increases 6 mV whereas the fcc sample increases 50 mV and the commercial Pt/C more than 350 mV. Thus, this study underlines the importance of controlling the crystal structure of nanoparticle electrocatalysts and shows the potential of using Ru as an alternative to Pt in alkaline conditions.","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78183530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Efficient heterogeneous Co(ii) species were fabricated via pyrolysis at 400 °C, rather than generally at 600–1000 °C.
高效的非均相Co(ii)通过热解在400°C，而不是一般在600-1000°C制备。
{"title":"Selective oxidation of substituted phenols with Co–N–C catalysts fabricated via low temperature heat treatment","authors":"Bairui Guo, Zhongtian Du, Xiaoyu Shen, Mengjing Han, Yanbin Zhao, Jingjie Luo, Changhai Liang","doi":"10.1039/d3cy00834g","DOIUrl":"https://doi.org/10.1039/d3cy00834g","url":null,"abstract":"Efficient heterogeneous Co(ii) species were fabricated via pyrolysis at 400 °C, rather than generally at 600–1000 °C.","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88725340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A special and controversial Cr/NNN ethylene oligomerization system delivering oligomers in a Schulz-Flory distribution, which was suggested to follow a metallacycle mechanism, has been systematically investigated by means of density...
{"title":"Unravelling the chain growth mechanism in Cr/NNN-catalysed ethylene oligomerization","authors":"Jiale Peng, Mengyu Zhu, Long Chen, Z. Liu","doi":"10.1039/d3cy00954h","DOIUrl":"https://doi.org/10.1039/d3cy00954h","url":null,"abstract":"A special and controversial Cr/NNN ethylene oligomerization system delivering oligomers in a Schulz-Flory distribution, which was suggested to follow a metallacycle mechanism, has been systematically investigated by means of density...","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87219997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An efficient catalyst is crucial for the production of hydrogen through methanol reforming. However, the current study of catalysts for this reaction primarily relies on time-consuming and labor-intensive experimental methods....
{"title":"Screening of steam reforming catalysts using unsupervised machine learning","authors":"Yujia Liu, Zhenwei Liang, Jiazhun Huang, Biqi Zhong, Xiaojun Yang, Tiejun Wang","doi":"10.1039/d3cy00754e","DOIUrl":"https://doi.org/10.1039/d3cy00754e","url":null,"abstract":"An efficient catalyst is crucial for the production of hydrogen through methanol reforming. However, the current study of catalysts for this reaction primarily relies on time-consuming and labor-intensive experimental methods....","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84367879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongxin Wang, Qiming Hu, Jiangyuan Qiu, Rui Guo, Xuanwen Liu
To satisfy the energy demand of modern society, seeking sustainable, clean and efficient energy production is claimed to be significant. Electrolytic water technology is an efficient and sustainable way to...
{"title":"Research progress of spinel CoFe2O4 as electrocatalysts for oxygen evolution reaction","authors":"Hongxin Wang, Qiming Hu, Jiangyuan Qiu, Rui Guo, Xuanwen Liu","doi":"10.1039/d3cy01013a","DOIUrl":"https://doi.org/10.1039/d3cy01013a","url":null,"abstract":"To satisfy the energy demand of modern society, seeking sustainable, clean and efficient energy production is claimed to be significant. Electrolytic water technology is an efficient and sustainable way to...","PeriodicalId":9643,"journal":{"name":"Catalysis Science & Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83886018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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