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Bimetallic TiO 2 Nanoparticles for Lignin-Based Model Compounds Valorization by Integrating an Optocatalytic Flow-Microreactor. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27248731. [PMID: 36557862 PMCID: PMC9785458 DOI: 10.3390/molecules27248731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
The challenge of improving the activity of TiO2 by modifying it with metals and using it for targeted applications in microreactor environments is an active area of research. Recently, microreactors have emerged as successful candidates for many photocatalytic reactions, especially for the selective oxidation process. The current work introduces ultrasound-assisted catalyst deposition on the inner walls of a perfluoro-alkoxy alkane (PFA) microtube under mild conditions. We report Cu-Au/TiO2 and Fe-Au/TiO2 nanoparticles synthesized using the sol-gel method. The obtained photocatalysts were thoroughly characterized by UV-Vis diffuse-reflectance spectroscopy (DRS), high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and N2 physisorption. The photocatalytic activity under UV (375 nm) and visible light (515 nm) was estimated by the oxidation of lignin-based model aromatic alcohols in batch and fluoropolymer-based flow systems. The bimetallic catalyst exhibited improved photocatalytic selective oxidation. Herein, four aromatic alcohols were individually investigated and compared. In our experiments, the alcohols containing hydroxy and methoxy groups (coniferyl and vanillin alcohol) showed high conversion (93% and 52%, respectively) with 8% and 17% selectivity towards their respective aldehydes, with the formation of other side products. The results offer an insight into ligand-to-metal charge transfer (LMCT) complex formation, which was found to be the main reason for the activity of synthesized catalysts under visible light.
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2
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Hartati, Firda PBD, Bahruji H, Bakar MB. Review on heterogeneous catalysts for the synthesis of perfumery chemicals via isomerization, acetalization and hydrogenation. FLAVOUR FRAG J 2021. [DOI: 10.1002/ffj.3671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hartati
- Department of Chemistry Faculty of Science and Technology Universitas Airlangga Surabaya Indonesia
| | - Putri Bintang Dea Firda
- Department of Chemistry Faculty of Science and Technology Universitas Airlangga Surabaya Indonesia
| | - Hasliza Bahruji
- Centre for Advanced Material and Energy Sciences Universiti Brunei Darussalam Gadong Brunei Darussalam
| | - Mohd Bakri Bakar
- Department of Chemistry Faculty of Science Universiti Teknologi Malaysia Johor Malaysia
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3
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Molefe T, Forbes RP, Coville NJ. Osmium@hollow Carbon Spheres as Fischer–Tropsch Synthesis Catalysts. Catal Letters 2020. [DOI: 10.1007/s10562-020-03347-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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4
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The Effect of Carbon Nanofibers Surface Properties in Hydrogenation and Dehydrogenation Reactions. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9235061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, carbon nanofiber-supported Pd nanoparticles were used in the hydrogenation of cinnamaldehyde and in the dehydrogenation of cinnamyl alcohol. The different graphitisation of the surface of the nanofibers and the amount of oxygen functionalisation significantly affected both activity and selectivity to the various reaction products. In particular, a decrease in nanoparticle dimensions and oxygen content resulted in an increase in overall activity for both of the studied reactions. Moreover, the selectivity to hydrocinnamaldehyde enhanced with increasing surface oxygen content in the cinnamaldehyde hydrogenation, while the selectivity to cinnamaldehyde was higher with low-functionalised nanofibers in the cinnamyl alcohol dehydrogenation. Finally, the most active catalyst proved also to be stable in consecutive runs.
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5
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Oregui-Bengoechea M, Agirre I, Iriondo A, Lopez-Urionabarrenechea A, Requies JM, Agirrezabal-Telleria I, Bizkarra K, Barrio VL, Cambra JF. Heterogeneous Catalyzed Thermochemical Conversion of Lignin Model Compounds: An Overview. Top Curr Chem (Cham) 2019; 377:36. [PMID: 31728773 DOI: 10.1007/s41061-019-0260-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/18/2019] [Indexed: 02/08/2023]
Abstract
Thermochemical lignin conversion processes can be described as complex reaction networks involving not only de-polymerization and re-polymerization reactions, but also chemical transformations of the depolymerized mono-, di-, and oligomeric compounds. They typically result in a product mixture consisting of a gaseous, liquid (i.e., mono-, di-, and oligomeric products), and solid phase. Consequently, researchers have developed a common strategy to simplify this issue by replacing lignin with simpler, but still representative, lignin model compounds. This strategy is typically applied to the elucidation of reaction mechanisms and the exploration of novel lignin conversion approaches. In this review, we present a general overview of the latest advances in the principal thermochemical processes applied for the conversion of lignin model compounds using heterogeneous catalysts. This review focuses on the most representative lignin conversion methods, i.e., reductive, oxidative, pyrolytic, and hydrolytic processes. An additional subchapter on the reforming of pyrolysis oil model compounds has also been included. Special attention will be given to those research papers using "green" reactants (i.e., H2 or renewable hydrogen donor molecules in reductive processes or air/O2 in oxidative processes) and solvents, although less environmentally friendly chemicals will be also considered. Moreover, the scope of the review is limited to those most representative lignin model compounds and to those reaction products that are typically targeted in lignin valorization.
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Affiliation(s)
- Mikel Oregui-Bengoechea
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain.
| | - Ion Agirre
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Aitziber Iriondo
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Alexander Lopez-Urionabarrenechea
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Jesus M Requies
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Iker Agirrezabal-Telleria
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Kepa Bizkarra
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - V Laura Barrio
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
| | - Jose F Cambra
- Department of Chemical and Environmental Engineering, School of Engineering, University of the Basque Country EHU/UPV, Plaza Ingeniero Torres Quevedo 1, 48013, Bilbao, Spain
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6
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Silver catalysts for liquid-phase oxidation of alcohols in green chemistry: Challenges and outlook. Catal Today 2019. [DOI: 10.1016/j.cattod.2018.06.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Lee SH, Kumari N, Dutta S, Jin X, Kumar A, Koo JH, Lee IS. Nanosilica-Confined Synthesis of Orthogonally Active Catalytic Metal Nanocrystals in the Compartmentalized Carbon Framework. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1901280. [PMID: 31074190 DOI: 10.1002/smll.201901280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 05/02/2019] [Indexed: 06/09/2023]
Abstract
Multifunctionalized porous catalytic nanoarchitectures are highly desirable for a variety of chemical transformations; however, selective installation of different catalysts with spatial and functional precision working synergistically and predictably, is highly challenging. Here, a synthetic strategy is developed toward the customizable combination of orthogonally reactive metal nanocrystals within interconnected carbon-cavities as a compartmentalized framework by employing aminated-silica-directed thermal solid-state nanoconfined synthesis of metal nanocrystals and endotemplating concomitant carbonization-mediated interlocking, as key processes. The main advantage of the strategy is the facility to choose any combination of metals, which can be further employed according to the desired application. The strategically synthesized compartmentalized multifunctional catalytic architectures of Pd-Pt@Com-CF regulate the O2 -mediated selective cascade oxidation reaction converting alcohol to acid with high yield and selectivity; and another Pt-Ir@Com-CF platform is demonstrated as a bifunctional electrocatalyst for oxygen reduction/evolution reactions.
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Affiliation(s)
- Seon Hee Lee
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Nitee Kumari
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Soumen Dutta
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Xing Jin
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Amit Kumar
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Jung Hun Koo
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - In Su Lee
- Creative Research Initiative Center for Nanospace-Confined Chemical Reactions (NCCR), Pohang, 37673, Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
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9
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Durndell LJ, Isaacs MA, Li C, Parlett CMA, Wilson K, Lee AF. Cascade Aerobic Selective Oxidation over Contiguous Dual-Catalyst Beds in Continuous Flow. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lee J. Durndell
- School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL4 8AA, U.K
| | - Mark A. Isaacs
- Department of Chemistry, University College London, London WC1E 6BT, U.K
| | - Chao’en Li
- CSIRO Energy, 71 Normanby Road, Clayton North, Victoria 3169, Australia
| | - Christopher M. A. Parlett
- School of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
- University of Manchester at Harwell, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K
| | - Karen Wilson
- School of Science, RMIT University, Melbourne VIC 3001, Australia
| | - Adam F. Lee
- School of Science, RMIT University, Melbourne VIC 3001, Australia
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10
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Guo P, Fu Q, Yildiz C, Chen YT, Ollegott K, Froese C, Kleist W, Fischer RA, Wang Y, Muhler M, Peng B. Regulating the size and spatial distribution of Pd nanoparticles supported by the defect engineered metal–organic framework HKUST-1 and applied in the aerobic oxidation of cinnamyl alcohol. Catal Sci Technol 2019. [DOI: 10.1039/c9cy00560a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A series of novel Pd@DE-HKUST-1(Cu/Pd) catalysts with different pydc feeding ratios were successfully synthesized. The size regime and the spatial distribution of the Pd NPs can be controlled by the amount of framework incorporated pydc.
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11
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Cheng X, Wang D, Liu J, Kang X, Yan H, Wu A, Gu Y, Tian C, Fu H. Ultra-small Mo 2N on SBA-15 as a highly efficient promoter of low-loading Pd for catalytic hydrogenation. NANOSCALE 2018; 10:22348-22356. [PMID: 30468225 DOI: 10.1039/c8nr06916f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Decreasing Pd usage whilst maintaining a superior performance is promising, but remains a challenge in the catalytic field. Herein, we have demonstrated the highly efficient promotion of Mo2N with a reduced amount of Pd for the liquid-phase hydrogenation reaction. The Mo2N (2-3 nm) was uniformly anchored onto mesoporous SBA-15 by using PMo12 as the Mo source. The small size and good dispersion of Mo2N is favourable for allowing their effective contact with post-loading Pd. This good contact is conducive to developing a synergistic catalyst, which was verified by studying the liquid-phase hydrogenation of p-nitrophenol (PNP) to p-aminophenol (PAP) with NaBH4 as the H source. The conversion ability of PNP to PAP on 1 wt% Pd-Mo2N/SBA-15 was vastly superior to 1 wt% Pd/SBA-15 and even better than 20 wt% Pd/SBA-15. The low-Pd, highly efficient catalysis is ascribed to the transfer of the electrons from Mo2N to Pd for the easy activation of H. The synergy can be affected by the type of support used. SBA-15 is superior to SiO2 and the other supports, which could be related to the large surface area and the plentiful number of pores on SBA-15, which is favourable to the dispersion of Pd and Mo2N, and the transfer/diffusion of the reactants. In particular, a highly efficient catalyst can be achieved at an even more reduced Pd loading (0.05 wt%). The current method describes the design of a highly efficient catalyst for the hydrogenation reaction using low amounts of noble metals.
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Affiliation(s)
- Xusheng Cheng
- Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, China.
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12
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Parlett CM, Aydin A, Durndell LJ, Frattini L, Isaacs MA, Lee AF, Liu X, Olivi L, Trofimovaite R, Wilson K, Wu C. Tailored mesoporous silica supports for Ni catalysed hydrogen production from ethanol steam reforming. CATAL COMMUN 2017. [DOI: 10.1016/j.catcom.2016.12.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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13
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Zhang X, Durndell LJ, Isaacs MA, Parlett CMA, Lee AF, Wilson K. Platinum-Catalyzed Aqueous-Phase Hydrogenation of d-Glucose to d-Sorbitol. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02369] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Xingguang Zhang
- European Bioenergy Research
Institute, Aston University, Birmingham B4 7ET, United Kingdom
| | - Lee J. Durndell
- European Bioenergy Research
Institute, Aston University, Birmingham B4 7ET, United Kingdom
| | - Mark A. Isaacs
- European Bioenergy Research
Institute, Aston University, Birmingham B4 7ET, United Kingdom
| | | | - Adam F. Lee
- European Bioenergy Research
Institute, Aston University, Birmingham B4 7ET, United Kingdom
| | - Karen Wilson
- European Bioenergy Research
Institute, Aston University, Birmingham B4 7ET, United Kingdom
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14
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Zhang X, Wilson K, Lee AF. Heterogeneously Catalyzed Hydrothermal Processing of C 5-C 6 Sugars. Chem Rev 2016; 116:12328-12368. [PMID: 27680093 DOI: 10.1021/acs.chemrev.6b00311] [Citation(s) in RCA: 197] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Biomass has been long exploited as an anthropogenic energy source; however, the 21st century challenges of energy security and climate change are driving resurgence in its utilization both as a renewable alternative to fossil fuels and as a sustainable carbon feedstock for chemicals production. Deconstruction of cellulose and hemicellulose carbohydrate polymers into their constituent C5 and C6 sugars, and subsequent heterogeneously catalyzed transformations, offer the promise of unlocking diverse oxygenates such as furfural, 5-hydroxymethylfurfural, xylitol, sorbitol, mannitol, and gluconic acid as biorefinery platform chemicals. Here, we review recent advances in the design and development of catalysts and processes for C5-C6 sugar reforming into chemical intermediates and products, and highlight the challenges of aqueous phase operation and catalyst evaluation, in addition to process considerations such as solvent and reactor selection.
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Affiliation(s)
- Xingguang Zhang
- European Bioenergy Research Institute, Aston University , Birmingham B4 7ET, United Kingdom
| | - Karen Wilson
- European Bioenergy Research Institute, Aston University , Birmingham B4 7ET, United Kingdom
| | - Adam F Lee
- European Bioenergy Research Institute, Aston University , Birmingham B4 7ET, United Kingdom
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15
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Noschese A, Buonerba A, Canton P, Milione S, Capacchione C, Grassi A. Highly efficient and selective reduction of nitroarenes into anilines catalyzed by gold nanoparticles incarcerated in a nanoporous polymer matrix: Role of the polymeric support and insight into the reaction mechanism. J Catal 2016. [DOI: 10.1016/j.jcat.2016.05.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Parlett CMA, Isaacs MA, Beaumont SK, Bingham LM, Hondow NS, Wilson K, Lee AF. Spatially orthogonal chemical functionalization of a hierarchical pore network for catalytic cascade reactions. NATURE MATERIALS 2016; 15:178-82. [PMID: 26569475 DOI: 10.1038/nmat4478] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/01/2015] [Indexed: 05/24/2023]
Abstract
The chemical functionality within porous architectures dictates their performance as heterogeneous catalysts; however, synthetic routes to control the spatial distribution of individual functions within porous solids are limited. Here we report the fabrication of spatially orthogonal bifunctional porous catalysts, through the stepwise template removal and chemical functionalization of an interconnected silica framework. Selective removal of polystyrene nanosphere templates from a lyotropic liquid crystal-templated silica sol-gel matrix, followed by extraction of the liquid crystal template, affords a hierarchical macroporous-mesoporous architecture. Decoupling of the individual template extractions allows independent functionalization of macropore and mesopore networks on the basis of chemical and/or size specificity. Spatial compartmentalization of, and directed molecular transport between, chemical functionalities affords control over the reaction sequence in catalytic cascades; herein illustrated by the Pd/Pt-catalysed oxidation of cinnamyl alcohol to cinnamic acid. We anticipate that our methodology will prompt further design of multifunctional materials comprising spatially compartmentalized functions.
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Affiliation(s)
| | - Mark A Isaacs
- European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK
| | - Simon K Beaumont
- Department of Chemistry, University of Durham, Durham DH1 3LE, UK
| | - Laura M Bingham
- Department of Chemistry, University of Durham, Durham DH1 3LE, UK
| | - Nicole S Hondow
- Institute for Materials Research, University of Leeds, Leeds LS2 9JT, UK
| | - Karen Wilson
- European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK
| | - Adam F Lee
- European Bioenergy Research Institute, Aston University, Birmingham B4 7ET, UK
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17
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Wu G, Brett GL, Cao E, Constantinou A, Ellis P, Kuhn S, Hutchings GJ, Bethell D, Gavriilidis A. Oxidation of cinnamyl alcohol using bimetallic Au–Pd/TiO2 catalysts: a deactivation study in a continuous flow packed bed microreactor. Catal Sci Technol 2016. [DOI: 10.1039/c6cy00232c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Deactivation of Au–Pd/TiO2 catalyst during oxidation in flow is attributed to Pd leaching and a complex effect of oxygen.
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Affiliation(s)
- Gaowei Wu
- Department of Chemical Engineering
- University College London
- London WC1E 7JE
- UK
| | | | - Enhong Cao
- Department of Chemical Engineering
- University College London
- London WC1E 7JE
- UK
| | | | - Peter Ellis
- Johnson Matthey Technology Centre
- Reading RG4 9NH
- UK
| | - Simon Kuhn
- Department of Chemical Engineering
- KU Leuven
- 3001 Leuven
- Belgium
| | | | - Donald Bethell
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD
- UK
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Wu HC, Chen TC, Lai NC, Yang CM, Wu JH, Chen YC, Lee JF, Chen CS. Synthesis of sub-nanosized Pt particles on mesoporous SBA-15 material and its application to the CO oxidation reaction. NANOSCALE 2015; 7:16848-16859. [PMID: 26403094 DOI: 10.1039/c5nr04943a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, we show that the size and shape of Pt nanoparticles in SBA-15 can be controlled through vacuum and air calcination. The vacuum-calcination/H2-reduction process is used to thermally treat a 0.2 wt% Pt(4+)/SBA-15 sample to obtain small 2D clusters and single atoms that can significantly increase Pt dispersion in SBA-15. Compared with thermal treatments involving air-calcination/H2-reduction, which result in ∼4.6 nm rod-like Pt particles, vacuum-calcination/H2-reduction can dramatically reduce the size of the Pt species to approximately 0.5-0.8 nm. The Pt particles undergoing air-calcination/H2-reduction have poor conversion efficiency because the fraction of terrace sites, the major sites for CO oxidation, on the rod-like Pt particles is small. In contrast, a large amount of low-coordinated Pt sites associated with 2D Pt species and single Pt atoms in SBA-15 is effectively generated through the vacuum-calcination/H2-reduction process, which may facilitate CO adsorption and induce strong reactivity toward CO oxidation. We investigated the effect of vacuum-calcination/H2-reduction on the formation of tiny 2D clusters and single atoms by characterizing the particles, elucidating the mechanism of formation, determining the active sites for CO oxidation and measuring the heat of CO adsorption.
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Affiliation(s)
- Hung-Chi Wu
- Center for General Education, Chang Gung University, 259, Wen-Hua 1st Rd., Guishan Dist., Taoyuan City 333, Taiwan, Republic of China.
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Costa JCS, Corio P, Rossi LM. Catalytic oxidation of cinnamyl alcohol using Au-Ag nanotubes investigated by surface-enhanced Raman spectroscopy. NANOSCALE 2015; 7:8536-8543. [PMID: 25895522 DOI: 10.1039/c5nr01064k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) enables ultrasensitive detection of adsorbed species at the catalyst surface. However, it is quite difficult to combine catalytic and SERS activities on the same material. Here we report the application of well-defined Au-Ag nanotubes as both SERS substrates and catalysts for the oxidation of cinnamyl alcohol. The species adsorbed on the catalyst surfaces at different reaction times were analyzed by SERS. The bimetallic nanotubes prepared via a simple galvanic replacement reaction are highly active in the oxidation of cinnamyl alcohol, but do not avoid a radical-chain reaction and the cleavage of the carbon-carbon double bond. A comparison between changes in bulk composition and the nature of adsorbed species at the surface of the catalyst over time suggests that cinnamaldehyde is formed on the catalyst surface (metal-catalyzed oxidation) and benzaldehyde is probably formed in the bulk solution via a radical-chain pathway. In the presence of 2,6-di-tert-butyl-4-methylphenol, the radical-chain reaction is suppressed and the oxidation reaction produces cinnamaldehyde.
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Affiliation(s)
- Jean Claudio Santos Costa
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, CP 26.077, 05513-970, São Paulo-SP, Brazil.
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Fina F, Ménard H, Irvine JTS. The effect of Pt NPs crystallinity and distribution on the photocatalytic activity of Pt-g-C3N4. Phys Chem Chem Phys 2015; 17:13929-36. [PMID: 25948234 DOI: 10.1039/c5cp00560d] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Loading of a co-catalyst on the surface of a semiconductor photocatalyst is often carried out without considering the effect of the loading procedure on the final product. The present study looks in detail at the effect that the loading method has on the morphology and final composition of platinum-based nanoparticles by means of XPS and TEM analysis. Additionally, reduction pre-treatments are performed to investigate how the coverage, crystallinity and composition of the NPs affect the photocatalytic H2 evolution. The activity of Pt-g-C3N4 can significantly be enhanced by controlling the properties of the co-catalyst NPs.
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Affiliation(s)
- F Fina
- School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, Scotland, UK.
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21
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Buonerba A, Noschese A, Grassi A. Highly Efficient Direct Aerobic Oxidative Esterification of Cinnamyl Alcohol with Alkyl Alcohols Catalysed by Gold Nanoparticles Incarcerated in a Nanoporous Polymer Matrix: A Tool for Investigating the Role of the Polymer Host. Chemistry 2014; 20:5478-86. [DOI: 10.1002/chem.201303880] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Indexed: 11/07/2022]
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