Catalysis Structure & Reactivity最新文献_第4页

Redox behavior of iron at the surface of an O(100) single crystal studied by ambient-pressure photoelectron spectroscopy 铁在O（100）单晶表面氧化还原行为的常压光电子能谱研究

Catalysis Structure & Reactivity Pub Date : 2017-03-03 DOI: 10.1080/2055074X.2016.1275379

L. Merte, J. Gustafson, M. Shipilin, Chu Zhang, E. Lundgren

引用次数: 7

High energy X-ray diffraction and IR spectroscopy of Pt/Al2O3 during CO oxidation in a novel catalytic reactor cell 新型催化反应器电池中CO氧化过程中Pt/Al2O3的高能x射线衍射和红外光谱

Catalysis Structure & Reactivity Pub Date : 2017-02-22 DOI: 10.1080/2055074X.2016.1274118

V. Marchionni, Anastasios Kambolis, M. Nachtegaal, O. Kröcher, D. Ferri

引用次数: 12

SAPO-37 microporous catalysts: revealing the structural transformations during template removal SAPO-37微孔催化剂:揭示模板去除过程中的结构转变

Catalysis Structure & Reactivity Pub Date : 2017-02-22 DOI: 10.1080/2055074X.2016.1262569

G. Kalantzopoulos, F. Lundvall, A. Lind, B. Arstad, D. Chernyshov, H. Fjellvåg, D. Wragg

{"title":"SAPO-37 microporous catalysts: revealing the structural transformations during template removal","authors":"G. Kalantzopoulos, F. Lundvall, A. Lind, B. Arstad, D. Chernyshov, H. Fjellvåg, D. Wragg","doi":"10.1080/2055074X.2016.1262569","DOIUrl":"https://doi.org/10.1080/2055074X.2016.1262569","url":null,"abstract":"Abstract We have studied the structural behavior of SAPO-37 during calcination using simultaneous in situ powder X-ray diffraction (PXRD) and mass spectroscopy (MS) in addition to ex situ thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). A spike in the unit cell volume corresponding to template removal (tracked using the occupancy of the crystallographic sites in the SAPO-37 cages) is revealed from the XRD data and is strongly correlated with the DSC curve. The occupancy of the different template molecules in the faujasite (FAU) and sodalite (SOD) cages is strongly related to the two mass loss steps observed in the TGA data. The templates act as a physical stabilizing agent, not allowing any substantial unit cell response to temperature changes until they are removed. The FAU cages and SOD cages have different thermal response to the combustion of each template. The FAU cages are mainly responsible for the unit cell volume expansion observed after the template combustion. This expansion seems to be related with residual coke from template combustion. We could differentiate between the thermal response of oxygen and T-atoms. The T–O–T angle between two double 6-rings and a neighboring T–O–T linkage shared by SOD and FAU had different response to the thermal events. We were able to monitor the changes in the positions of oxygen and T-atoms during the removal of TPA+ and TMA+. Large changes to the framework structure at the point of template removal may have a significant effect on the long-term stability of the material in its activated form.","PeriodicalId":43717,"journal":{"name":"Catalysis Structure & Reactivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/2055074X.2016.1262569","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42313973","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}

引用次数: 5

Towards the interrogation of the behaviour of a single nanoparticle under realistic catalytic reaction conditions 对现实催化反应条件下单个纳米粒子行为的研究

Catalysis Structure & Reactivity Pub Date : 2017-02-21 DOI: 10.1080/2055074X.2016.1277655

D. Martin, Donato Decarolis, R. Tucoulou, G. Martínez-Criado, Andrew M. Beale

{"title":"Towards the interrogation of the behaviour of a single nanoparticle under realistic catalytic reaction conditions","authors":"D. Martin, Donato Decarolis, R. Tucoulou, G. Martínez-Criado, Andrew M. Beale","doi":"10.1080/2055074X.2016.1277655","DOIUrl":"https://doi.org/10.1080/2055074X.2016.1277655","url":null,"abstract":"Abstract It is well known that particle size plays an important role in catalytic activity although the reason(s) why significant changes in activity are observed to occur with small changes in size are not well understood. The presence of particular facets, metal-support interactions, and redox state etc., are also capable of playing a role. The difficulty in realising which features are pertinent in a catalytic process stems from issues regarding sample complexity in typical heterogeneous catalysts, as well as technical challenges with instruments used to investigate samples in terms of their sensitivity and capability to distinguish between a specific vs. ensemble response in catalytically active vs. spectator species. We show here how the combination of using a synthesis method which achieves a discrete dispersion of metal Pd nanoparticles with a very narrow particle size distribution (σ ~ 1 nm) in combination with nano-beam X-ray spectroscopy allows us to follow the changes in redox state with time. Importantly, the data are obtained in one example, from an illuminating spot containing ca. 20 nanoparticles with an extremely small size distribution.","PeriodicalId":43717,"journal":{"name":"Catalysis Structure & Reactivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/2055074X.2016.1277655","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49227741","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}

引用次数: 5

Effect of Cu content on the bimetallic Pt–Cu catalysts for propane dehydrogenation Cu含量对丙烷脱氢双金属Pt-Cu催化剂性能的影响

Catalysis Structure & Reactivity Pub Date : 2017-02-21 DOI: 10.1080/2055074X.2016.1263177

Zixue Ma, Zhenwei Wu, Jeffrey T. Miller

{"title":"Effect of Cu content on the bimetallic Pt–Cu catalysts for propane dehydrogenation","authors":"Zixue Ma, Zhenwei Wu, Jeffrey T. Miller","doi":"10.1080/2055074X.2016.1263177","DOIUrl":"https://doi.org/10.1080/2055074X.2016.1263177","url":null,"abstract":"Abstract Silica supported, 2 nm Pt and Pt–Cu catalysts with different Cu:Pt atomic ratios and similar size were evaluated for propane dehydrogenation at 550 °C. Monometallic Pt showed low propylene selectivity of 61% at 20% conversion and a TOR of 0.06 s−1. For the Pt–Cu catalysts, the dehydrogenation selectivity and TOR continuously increased with increasing Cu level in the nanoparticle, to eventually 96% selective at 20% conversion with a TOR of 0.98 s−1 for a catalyst with a Cu:Pt atomic ratio of 7.3. Synchrotron in situ X-ray diffraction and X-ray absorption spectroscopy analysis showed that Pt–Cu catalysts with increasing Cu loading formed solid solution type bimetallic structures. For example, a Pt–Cu catalyst with Cu:Pt atomic ratio of 7.3 formed solid solution containing 87% Cu. In this catalyst, the Pt active sites were geometrically isolated by the inactive metallic Cu, which was suggested to be responsible for high selectivity to propane dehydrogenation. The Cu neighbors surrounding the Pt also likely modified the energy level of Pt 5d orbitals and contribute to a TOR about 16 times higher than that of monometallic Pt.","PeriodicalId":43717,"journal":{"name":"Catalysis Structure & Reactivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/2055074X.2016.1263177","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46921108","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}

引用次数: 26

Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures Cl对负载型PdO在乙醇/水溶剂混合物中还原的影响

Catalysis Structure & Reactivity Pub Date : 2017-02-21 DOI: 10.1080/2055074X.2016.1267296

J. Brazier, M. Newton, Elena M. Barreiro, S. Parry, L. A. Adrio, Christopher J. Mulligan, K. Hellgardt, K. K. Hii, P. Thompson, Rachel Nichols, B. Nguyen

引用次数: 4

Sulphidation study of a dried Ni/Al2O3 catalyst by time-resolved XAS-MS combined with in situ Raman spectroscopy and multivariate Quick-XAS data analysis 用时间分辨XAS-MS结合原位拉曼光谱和多元Quick-XAS数据分析研究干燥Ni/Al2O3催化剂的硫化作用

Catalysis Structure & Reactivity Pub Date : 2017-02-16 DOI: 10.1080/2055074X.2016.1263178

A. Rochet, Aline Ribeiro Passos, C. Legens, V. Briois

引用次数: 6

Study of methane oxidation over alumina supported Pd–Pt catalysts using operando DRIFTS/MS and in situ XAS techniques 用DRIFTS/MS和原位XAS技术研究氧化铝负载Pd–Pt催化剂上甲烷的氧化

Catalysis Structure & Reactivity Pub Date : 2017-02-16 DOI: 10.1080/2055074X.2017.1281717

N. Martin, Johan Nilsson, M. Skoglundh, Emma C. Adams, Xueting Wang, G. Smedler, A. Raj, D. Thompsett, G. Agostini, S. Carlson, K. Norén, P. Carlsson

{"title":"Study of methane oxidation over alumina supported Pd–Pt catalysts using operando DRIFTS/MS and in situ XAS techniques","authors":"N. Martin, Johan Nilsson, M. Skoglundh, Emma C. Adams, Xueting Wang, G. Smedler, A. Raj, D. Thompsett, G. Agostini, S. Carlson, K. Norén, P. Carlsson","doi":"10.1080/2055074X.2017.1281717","DOIUrl":"https://doi.org/10.1080/2055074X.2017.1281717","url":null,"abstract":"Graphical Abstract Abstract Methane oxidation over Pd–Pt/ model catalysts calcined at three different conditions is investigated using operando diffuse reflectance infrared Fourier transform spectroscopy and mass spectrometry, and in situ X-ray absorption spectroscopy while cycling the feed gas stoichiometry between lean (net-oxidising) and rich (net-reducing) conditions. When calcined in air, alloy Pd–Pt nanoparticles are present only on catalysts subjected to elevated temperature () whereas calcination at lower temperature (500 ) leads to segregated Pt and Pd nanoparticles on the support. Here, we show that the alloy Pd–Pt nanoparticles undergo reversible changes in surface structure and composition during transient methane oxidation exposing a PdO surface during lean conditions and a metallic Pd–Pt surface (Pd enriched) under rich conditions. Alloyed particles seem more active for methane oxidation than their monometallic counterparts and, furthermore, an increased activity for methane oxidation is clearly observed under lean conditions when PdO has developed on the surface, analogous to monometallic Pd catalysts. Upon introducing rich conditions, partial oxidation of methane dominates over total oxidation forming adsorbed carbonyls on the noble metal particles. The carbonyl spectra for the three samples show clear differences originating from different surfaces exposed by alloyed vs. non-alloyed particles. The kinetics of the noble metal oxidation and reduction processes as well as carbonyl formation during transient methane oxidation are discussed.","PeriodicalId":43717,"journal":{"name":"Catalysis Structure & Reactivity","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2017-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/2055074X.2017.1281717","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41309907","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}

引用次数: 13

Understanding the role of promoters in catalysis: operando XAFS/DRIFTS study of CeOx/Pt/Al2O3 during CO oxidation CO氧化过程中CeOx/Pt/Al2O3的XAFS/DRIFTS研究促进剂在催化中的作用

Catalysis Structure & Reactivity Pub Date : 2017-02-14 DOI: 10.1080/2055074X.2017.1278890

E. Gibson, E. Crabb, D. Gianolio, A. Russell, D. Thompsett, P. Wells

引用次数: 7

Time-resolved, in situ DRIFTS/EDE/MS studies on alumina supported Rh catalysts: effects of ceriation on the Rh catalysts in the process of CO oxidation 时间分辨、原位漂移/EDE/MS研究氧化铝负载Rh催化剂:CO氧化过程中铈对Rh催化剂的影响

Catalysis Structure & Reactivity Pub Date : 2017-02-14 DOI: 10.1080/2055074X.2016.1266762

A. Kroner, M. Newton, M. Tromp, A. Russell, A. Dent, J. Evans

引用次数: 1