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Arribas D, Villalobos-Vilda V, Tosi E, Lacovig P, Baraldi A, Bignardi L, Lizzit S, Martínez JI, de Andres PL, Gutiérrez A, Martín-Gago JÁ, Merino P. In situ observation of the on-surface thermal dehydrogenation of n-octane on Pt(111). NANOSCALE 2023; 15:14458-14467. [PMID: 37458500 DOI: 10.1039/d3nr02564k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The catalytic dehydrogenation of alkanes constitutes a key step for the industrial conversion of these inert sp3-bonded carbon chains into other valuable unsaturated chemicals. To this end, platinum-based materials are among the most widely used catalysts. In this work, we characterize the thermal dehydrogenation of n-octane (n-C8H18) on Pt(111) under ultra-high vacuum using synchrotron-radiation X-ray photoelectron spectroscopy, temperature-programmed desorption and scanning tunneling microscopy, combined with ab initio calculations. At low activation temperatures, two different dehydrogenation stages are observed. At 330 K, n-C8H18 effectively undergoes a 100% regioselective single C-H bond cleavage at one methyl end. At 600 K, the chemisorbed molecules undergo a double dehydrogenation, yielding double bonds in their carbon skeletons. Diffusion of the dehydrogenated species leads to the formation of carbon molecular clusters, which represents the first step towards poisoning of the catalyst. Our results reveal the chemical mechanisms behind the first stages of alkane dehydrogenation on a platinum model surface at the atomic scale, paving the way for designing more efficient dehydrogenation catalysts.
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Affiliation(s)
- Daniel Arribas
- Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Inés de la Cruz, 3, Spain.
| | | | - Ezequiel Tosi
- Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Inés de la Cruz, 3, Spain.
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, Trieste, Italy
| | - Paolo Lacovig
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, Trieste, Italy
| | - Alessandro Baraldi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, Trieste, Italy
- Physics Department, University of Trieste, Via Valerio 2, 34127 Trieste, Italy
| | - Luca Bignardi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, Trieste, Italy
| | - Silvano Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, Trieste, Italy
| | - José Ignacio Martínez
- Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Inés de la Cruz, 3, Spain.
| | - Pedro Luis de Andres
- Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Inés de la Cruz, 3, Spain.
- On leave of absence at nanoteeche@surfaces Laboratory, Swiss Federal Laboratories for Materials Science and Technology, 8600-Dübendorf, Switzerland
| | - Alejandro Gutiérrez
- Applied Physics Department, Universidad Autónoma de Madrid, Calle Francisco Tomás y Valiente, 7, 28049 Madrid, Spain
- Instituto Nicolás Cabrera, Cantoblanco, Calle Francisco Tomás y Valiente, 7, 28049 Madrid, Spain
| | | | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Inés de la Cruz, 3, Spain.
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Wang J, Zhu P, Liu C, Liu H, Zhang W, Zhang X. Regulating Encapsulation of Small Pt Nanoparticles inside Silicalite-1 Zeolite with the Aid of Sodium Ions for Enhancing n-Hexane Reforming. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c01196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jinshan Wang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Peng Zhu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Cun Liu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Haiou Liu
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
| | - Wei Zhang
- Dalian Institute of Chemical Physics Xi’an Clean Energy (Chemical) Research Institute, Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi’an 710065, China
| | - Xiongfu Zhang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
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Yan M, Xu D, Wu B, Yang Y, Li Y. Insight into different performance of Pt/KL catalysts for n-alkane (C6-C8) aromatization: catalytic role of zeolite channels. Catal Sci Technol 2022. [DOI: 10.1039/d1cy02090k] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zeolite channel architecture was vital to catalytic activity and products distribution during the naphtha reforming, which could be effectively utilized by designing the locations of active sites. Herein, uniformly dispersed...
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Del Campo P, Martínez C, Corma A. Activation and conversion of alkanes in the confined space of zeolite-type materials. Chem Soc Rev 2021; 50:8511-8595. [PMID: 34128513 DOI: 10.1039/d0cs01459a] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Microporous zeolite-type materials, with crystalline porous structures formed by well-defined channels and cages of molecular dimensions, have been widely employed as heterogeneous catalysts since the early 1960s, due to their wide variety of framework topologies, compositional flexibility and hydrothermal stability. The possible selection of the microporous structure and of the elements located in framework and extraframework positions enables the design of highly selective catalysts with well-defined active sites of acidic, basic or redox character, opening the path to their application in a wide range of catalytic processes. This versatility and high catalytic efficiency is the key factor enabling their use in the activation and conversion of different alkanes, ranging from methane to long chain n-paraffins. Alkanes are highly stable molecules, but their abundance and low cost have been two main driving forces for the development of processes directed to their upgrading over the last 50 years. However, the availability of advanced characterization tools combined with molecular modelling has enabled a more fundamental approach to the activation and conversion of alkanes, with most of the recent research being focused on the functionalization of methane and light alkanes, where their selective transformation at reasonable conversions remains, even nowadays, an important challenge. In this review, we will cover the use of microporous zeolite-type materials as components of mono- and bifunctional catalysts in the catalytic activation and conversion of C1+ alkanes under non-oxidative or oxidative conditions. In each case, the alkane activation will be approached from a fundamental perspective, with the aim of understanding, at the molecular level, the role of the active sites involved in the activation and transformation of the different molecules and the contribution of shape-selective or confinement effects imposed by the microporous structure.
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Affiliation(s)
- Pablo Del Campo
- Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain.
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Xu H, Li Z, Meng S, Jarvis J, Song H. Highly selective skeletal isomerization of cyclohexene over zeolite-based catalysts for high-purity methylcyclopentene production. Commun Chem 2021; 4:34. [PMID: 36697580 PMCID: PMC9814423 DOI: 10.1038/s42004-021-00472-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 02/09/2021] [Indexed: 01/28/2023] Open
Abstract
Cyclohexene skeletal isomerization towards methylcyclopentene is an economically favorable process due to the higher added value of the product. Traditional oxide-based catalysts face the challenge of achieving both high activity and stability. In this work, cyclohexene skeletal isomerization is achieved under mild conditions over designed zeolite-based catalysts with 96.8 wt.% liquid yield, 95.8 wt.% selectivity towards methylcyclopentene and satisfactory stability for multiple runs. The favorable performance is attributed to the unique acidic, structural and morphological features of the optimized cobalt/NaUZSM-5 catalyst. Further experimental data and DFT studies suggest that a carboncationic mechanism might be followed and that the reaction mainly occurs within the internal pores of the zeolite structures.
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Affiliation(s)
- Hao Xu
- grid.22072.350000 0004 1936 7697Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB Canada
| | - Zhaofei Li
- grid.22072.350000 0004 1936 7697Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB Canada
| | - Shijun Meng
- grid.22072.350000 0004 1936 7697Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB Canada
| | - Jack Jarvis
- grid.22072.350000 0004 1936 7697Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB Canada
| | - Hua Song
- grid.22072.350000 0004 1936 7697Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB Canada
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