Graham J. Hutchings

University of South Wales, Понтиприте, Wales, United Kingdom

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Publications (690)2762.57 Total impact

  • Ren Su · Flemming Besenbacher · Graham Hutchings ·
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    ABSTRACT: One of the most significant investigations on heterogeneous photocatalytic process can be dated back to the 1970s, when Fujishima and Honda showed that the TiO2 electrode is capable of water splitting under suitable electromagnetic irradiation. Since then TiO2 based materials have become the dominant photocatalyst and have been investigated for decades due to their abundance, non-toxicity, and relatively high reactivity. However, the bandgap of pristine TiO2 is larger than 3 eV, which can only absorb light that has a wavelength of less than 400 nm. Unfortunately, this portion of photons only corresponds to 4-5% of the solar spectrum, which has limited the application of photocatalysis at an industrial scale. Moreover, the conduction band position of TiO2 is only slightly negative relative to that of the proton reduction potential, resulting in a relatively poor reduction power for solar-to-fuel conversion. Therefore, the development of alternative photocatalysts with visible light absorption and unable properties is essential in the application of photocatalysis techniques. In this chapter, we will consider the most popular photocatalyst systems other than TiO2. Their synthesis methods, characteristics, optimisations and design will be presented. Last but not least, the design and synthesis of promoters, which play a very essential role in photocatalyst systems, will also be demonstrated at the end of this chapter.
    Heterogeneous Photocatalysis, 1 edited by Juan Carlos Colmenares, Yi-Jun Xu, 11/2015: chapter Chapter 4 Alternative materials to TiO2: pages 40; Springer-Verlag Berlin Heidelberg., ISBN: 978-3-662-48717-4
  • Peter Johnston · Nicholas Carthey · Graham J Hutchings ·
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    ABSTRACT: Vinyl chloride monomer (VCM) is a major chemical intermediate for the manufacture of polyvinyl chloride (PVC) which is the third most important polymer in use today. Hydrochlorination of acetylene is a major route for the production of vinyl chloride since production of the monomer is based in regions of the world where coal is abundant. Until now mercuric chloride supported on carbon is used as the catalyst in the commercial process and this exhibits severe problems associated with catalyst lifetime and mercury loss. It has been known for over thirty years that gold is a superior catalyst but it is only now that it is being commercialised. In this perspective we discuss the use and disadvantages of the mercury catalyst and the advent of the gold catalysts for this important reaction. The nature of the active site and the possible reaction mechanism is discussed. Recent advances in the design and preparation of active gold catalysts containing ultra-low levels of gold are described. In the final part a view to the future of this chemistry will be discussed as well as the possible avenues for the commercial potential of gold catalysis.
    Journal of the American Chemical Society 11/2015; DOI:10.1021/jacs.5b07752 · 12.11 Impact Factor
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    ABSTRACT: Metal co-catalysts are essential for enhancing photocatalytic performance, especially in reduction reactions using semiconductor photocatalyst materials as a consequence of the reduced recombination kinetics of charge carriers by spatial charge separation. Generally Au, Pd, Pt, and their alloys are more promising candidates than Ag for photocatalytic H2 evolution experiments, although Ag can trap more electrons having more negative reduction potential than that of Au, Pd, and Pt. Here we have synthesized and examined well-defined Au, Ag, and core-shell structured Au–Ag nanoparticles as co-catalysts for TiO2 in photocatalytic H2 evolution. By varying the dissolved oxygen in the reaction suspension, we found that selective photocatalytic reduction can be achieved by fine tuning the co-catalyst materials. Whilst Au NPs are superior for proton reduction, Ag NPs exhibits excellent performance for oxygen reduction. All core-shell structured Au–Ag NPs show non-selectivity in photocatalytic reduction of proton and oxygen.
    Applied Catalysis A: General 10/2015; DOI:10.1016/j.apcata.2015.10.023 · 3.94 Impact Factor

  • Catalysis Today 10/2015; DOI:10.1016/j.cattod.2015.09.041 · 3.89 Impact Factor
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    ABSTRACT: The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.
    Nature Chemistry 09/2015; 7(12). DOI:10.1038/nchem.2345 · 25.33 Impact Factor
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    Giacomo Marco Lari · Ewa Nowika · David J Morgan · Simon A Kondrat · Graham J Hutchings ·

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    ABSTRACT: Vanadium phosphate catalysts have been widely studied for the selective oxidation of alkanes to a variety of products, including maleic and phthalic anhydride. More recently they are starting to find use as low temperature liquid phase oxidation catalysts. For all these applications the synthesis of the precursor is key to the performance of the final catalyst. Changes in the preparation procedure can alter the morphology, surface area, crystallinity, oxidation state and the phases present in the final catalyst which can all affect the selectivity and/or activity of the catalyst. Adding a diblock copolymer, poly(acrylic acid-co-maleic acid) (PAAMA), during the synthesis was found to influence the crystallinity and morphology of the VOHPO4·0.5H2O precursors obtained. An optimal level of copolymer was found to form precursors that showed a faster, more efficient, activation to the active catalyst, whereas high amounts of copolymer formed thin platelets, which were prone to oxidise to undesirable V5+ phases under reaction conditions, reducing the selectivity to maleic anhydride.
    Catalysis Science & Technology 09/2015; DOI:10.1039/C5CY01260K · 5.43 Impact Factor
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    ABSTRACT: Precious metal nanoparticles supported on magnesium-aluminum hydrotalcite (HT), TiO2 , and MgO were prepared by sol immobilization and assessed for the catalytic oxidation of octanol, which is a relatively unreactive aliphatic alcohol, with molecular oxygen as the oxidant under solvent- and base-free conditions. Compared with the TiO2 - and MgO-supported catalysts, platinum HT gave the highest activity and selectivity towards the aldehyde. The turnover number achieved for the platinum HT catalyst was >3700 after 180 min under mild reaction conditions. Moreover, the results for the oxidation of different substrates indicate that a specific interaction of octanal with the platinum HT catalyst could lead to deactivation of the catalyst. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    ChemSusChem 09/2015; 8(19). DOI:10.1002/cssc.201500503 · 7.66 Impact Factor
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    ABSTRACT: The hydrogenation of lactic acid to form 1,2-propanediol has been investigated using Ru nanoparticles supported on carbon as a catalyst. Two series of catalysts which were prepared by wet impregnation and sol-immobilization were investigated. Their activity was contrasted with that of a standard commercial Ru/C catalyst (all catalysts comprise 5 wt % Ru). The catalyst prepared using sol-immobilization was found to be more active than the wet impregnation materials. In addition, the catalyst made by sol-immobilization was initially more active than the standard commercial catalyst. However, when reacted for an extended time or with successive reuse cycles, the sol-immobilized catalyst became less active, whereas the standard commercial catalyst became steadily more active. Furthermore, both catalysts exhibited an induction period during the first 1000 s of reaction. Detailed scanning transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption fine structure analysis data, when correlated with the catalytic performance results, showed that the high activity can be ascribed to highly dispersed Ru nanoparticles. Although the sol-immobilization method achieved these optimal discrete Ru nanoparticles immediately, as can be expected from this preparation methodology, the materials were unstable upon reuse. In addition, surface lactide species were detected on these particles using X-ray photoelectron spectroscopy, which could contribute to their deactivation. The commercial Ru/C catalysts, on the other hand, required treatment under reaction conditions to change from raft-like morphologies to the desired small nanoparticle morphology, during which time the catalytic performance progressively improved.
    ACS Catalysis 09/2015; 5(9-9):5047-5059. DOI:10.1021/acscatal.5b00625 · 9.31 Impact Factor

  • Catalysis Today 09/2015; DOI:10.1016/j.cattod.2015.09.011 · 3.89 Impact Factor
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    Giacomo Marco Lari · Ewa Nowika · David J Morgan · Simon A Kondrat · Graham J Hutchings ·
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    ABSTRACT: The sol immobilisation technique, in which a stabilising ligand (such as polyvinyl alcohol or polyvinyl pyridine) can be used to tune metal particle size and composition, has become a valuable method of making supported nanoparticle catalysts. An unfortunate consequence of the stabilising ligand is that often access of reactant molecules to the metal nanoparticle surface is impeded. Several methods have been proposed for the removal of these ligands, though determination of the degree of their success is difficult. Here, we demonstrate the use of in situ infrared and UV-Vis spectroscopy to elucidate the access of carbon monoxide to the surface of Au/TiO2 catalysts before and after various ligand removal treatments. These were contrasted with a catalyst prepared by deposition precipitation prepared in the absence of stabilising ligand as a control. Changes were observed in the infrared spectrum, with the wavenumber of carbon monoxide linearly bonded to Au for catalysts shifting before and after ligand removal, which correlated well with the activity of the catalyst for carbon monoxide oxidation. Also the extent of shifting of the Au surface resonance plasmon band on the addition of carbon monoxide, observed by UV-Vis, also correlated well with catalyst activity. These simple methods can be used to determine the quantity of exposed metal sites after a ligand removal treatment and so determine the treatments effectiveness.
    Physical Chemistry Chemical Physics 08/2015; 17(35). DOI:10.1039/C5CP02512E · 4.49 Impact Factor
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    ABSTRACT: The selective oxidation of lower alkanes, such as ethane, remains a major research challenge in catalysis. In this study Fe and Cu containing zeolites are investigated as catalysts for the production of C2 oxygenated products from ethane using H2O2 as an oxidant. We utilise a trickle bed reactor to effectively control the contact time between reactants and catalyst to minimise C-C scission and over oxidation to COx. Reaction conditions such as temperature, pressure and reactant concentration in combination with Fe and Cu content of the catalysts are investigated to optimise conversion and selectivity to C2 oxygenated products. A marked effect is observed upon increasing pressure between 1 and 30 bar, as the oxygenate selectivity increases from 46% to 98%. Single pass conversion of ethane (22%) to acetic acid (73%, 16% yield) has been observed using a Fe/ZSM-5 catalyst under the optimum conditions. Catalysts are investigated for stability, and are observed to undergo no apparent deactivation under test conditions, despite low levels of Fe leaching. Through characterisation and assessment of leached Fe/ZSM-5 catalysts, we show that catalytic activity might be attributed to Fe species within the zeolite's channels and that surface FexOy are spectator species. Finally, relatively high selectivity to ethene (38%, 1% yield) has been observed with Cu containing materials under these mild reaction conditions.

  • ChemInform 07/2015; 46(29). DOI:10.1002/chin.201529292
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    ABSTRACT: The selective hydrogenation of furfuryl alcohol was investigated at room temperature by using supported palladium catalysts. The catalysts are very selective to the formation of 2-methylfuran. Furthermore, the addition of tin to palladium showed similar catalytic activity, but was more selective to tetrahydrofurfuryl alcohol. Variation of the Sn/Pd ratio has shown a considerable and interesting effect on the selectivity pattern. Addition of a small amount of Sn (1 wt %) shifted the selectivity towards tetrahydrofurfuryl alcohol and methyltetrahydrofuran, which are ring-saturated molecules. Increasing the tin ratio further decreased the catalytic activity and also showed very poor selectivity to either of these products.
    ChemCatChem 06/2015; 7(14). DOI:10.1002/cctc.201500242 · 4.56 Impact Factor
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    ABSTRACT: TiO2 with tailored anatase/rutile composition has been prepared from the supercritical antisolvent (SAS) precipitation of a range of titanium alkoxides. The calcination of the SAS TiO2 was monitored by in situ powder X-ray diffraction to determine the optimal calcination conditions for the formation of a mixed anatse/rutile phase TiO2. The SAS precipitated material calcined at 450 °C produced a predominantly anatase support while calcination at 750 °C resulted in a 90 wt% anatase and 10 wt% rutile TiO2. 5 wt% AuPd was added to the SAS TiO2 using an impregnation technique, with exceptional dispersion of the metals being observed by transmission electron microscopy. Mean metal particle sizes were determined to be below 1 nm for both anatase and anatase/rutile SAS TiO2 materials. These catalysts were found to be highly active for the selective oxidation of benzyl alcohol and the direct synthesis of hydrogen peroxide. In addition the anatase/rutile SAS TiO2 was found to have comparable activity to commercial anatase/rutile mixed phase TiO2 for the photocatalytic splitting of water for hydrogen production.
    Applied Catalysis A General 05/2015; 504. DOI:10.1016/j.apcata.2015.02.023 · 3.94 Impact Factor
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    ABSTRACT: The control over both the dispersion and the particle size distribution of supported precious metal nanoparticles used in heterogeneous catalysts is of paramount importance. Here, we demonstrate the successful formation of highly accessible and well dispersed gold-palladium nanoparticles, stabilised with two-dimensional graphene oxide, that itself is dispersed by intercalated titania particles to form ternary hybrid catalysts. In this application, graphene oxide acts as an effective substitute for the more conventional polymer ligands that are used to stabilize nanoparticles in a sol-immobilisation procedure. The particle size distribution can be adjusted by varying the graphene oxide-to-metal mass ratio. The addition of titania efficiently hinders the stacking and agglomeration of the supported metal on graphene oxide sheets, facilitating diffusion of oxygen and reactants to the catalyst surface. This gold-palladium / graphene oxide / titania “ternary’ catalyst has been tested for the selective oxidation of a range of alcohols. The resulting optimised catalyst exhibits a comparable activity to a sol-immobilised derived catalyst where the metal nanoparticles are stabilized by polyvinyl alcohol ligands, with the graphene oxide-stabilized hybrid catalyst having enhanced stability. We consider that the novel strategy of supporting metal nanoparticles described here can also be adopted to synthesize a wide range of high activity, stable heterogeneous catalysts for other reactions.
    ACS Catalysis 04/2015; 5(6):150429121546003. DOI:10.1021/acscatal.5b00480 · 9.31 Impact Factor
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    ABSTRACT: Glycerol is an important byproduct of biodiesel production, and it is produced in significant amounts by transesterification of triglycerides with methanol. Due to the highly functionalized nature of glycerol, it is an important biochemical that can be utilized as a platform chemical for the production of high-added-value products. At present, research groups in academia and industry are exploring potential direct processes for the synthesis of useful potential chemicals using catalytic processes. Over the last 10 years, there has been huge development of potential catalytic processes using glycerol as the platform chemical.
    Accounts of Chemical Research 04/2015; 48(5). DOI:10.1021/ar500426g · 22.32 Impact Factor
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    ABSTRACT: The selective oxidation of linear alkanes with molecular oxygen under mild conditions remains a challenging topic in the field of catalysis. In this study we investigate the co-oxidation of C-H bonds in substrates with different relative reactivities, the aim being to couple the oxidised products in situ to form the corresponding esters. Initial attempts were made to co-oxidise octane with toluene to form octyl benzoate using Au-Pd catalysts. During the study the oxidation of octane in the presence of benzaldehyde, an oxidation product of toluene, was also investigated in order to demonstrate the potential feasibility of the reaction. This work summarises our attempts to show whether a co-oxidation system could be an effective way to oxidise linear alkanes.
    04/2015; 5(8). DOI:10.1039/C5CY00453E
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    ABSTRACT: A detailed study of the selective oxidation of cyclohexane has been performed using bimetallic gold-palladium catalysts supported on magnesium oxide. Mono-metallic supported gold or palladium catalysts show limited activity for cyclohexane oxidation. However, a significantly enhanced catalytic performance is observed when supported gold-palladium alloy catalysts are used for this particular reaction. This synergy is observed for alloys spanning a wide range of gold-to-palladium molar ratios. Mechanistic studies reveal a promotion effect that occurs from alloying palladium with gold on the supported catalyst, which significantly improves the homo-cleavage of the O-O bond in cyclohexyl hydroperoxide, an important intermediate species in cyclohexane oxidation.
    Applied Catalysis A General 03/2015; DOI:10.1016/j.apcata.2015.02.034 · 3.94 Impact Factor
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    ABSTRACT: A quantitative NMR protocol has been developed to study the ruthenium-ion-catalyzed oxidation of a range of alkylated polyaromatics, as reported by S. H. Taylor et al. in their Full Paper on page 4285 ff. RuO4 acts as a very selective catalyst, targeting the oxidation of aromatic carbon in preference to aliphatic carbon in alkyl-substituted polyaromatic hydrocarbons.
    Chemistry 03/2015; 21(11):4165-4165. DOI:10.1002/chem.201590037 · 5.73 Impact Factor

Publication Stats

20k Citations
2,762.57 Total Impact Points


  • 2002-2015
    • University of South Wales
      Понтиприте, Wales, United Kingdom
  • 1998-2015
    • Cardiff University
      • School of Chemistry
      Cardiff, Wales, United Kingdom
  • 2005-2013
    • Lehigh University
      • Department of Materials Science and Engineering
      Bethlehem, PA, United States
  • 1990-2011
    • University of Liverpool
      • Department of Chemistry
      Liverpool, England, United Kingdom
  • 2010
    • University of Aberdeen
      • Department of Chemistry
      Aberdeen, Scotland, United Kingdom
    • University of Cambridge
      • Department of Chemical Engineering and Biotechnology
      Cambridge, England, United Kingdom
  • 1999-2010
    • University of Reading
      • Department of Chemistry
      Reading, England, United Kingdom
  • 1997-2010
    • University of Wales
      • Department of Chemistry
      Cardiff, Wales, United Kingdom
  • 1985-2010
    • University of the Witwatersrand
      • School of Chemistry
      Johannesburg, Gauteng, South Africa
  • 2006
    • Universität Stuttgart
      • Institute of Organic Chemistry
      Stuttgart, Baden-Württemberg, Germany
  • 2003
    • University of California, Berkeley
      • Department of Materials Science and Engineering
      Berkeley, California, United States
  • 2001
    • Loughborough University
      • Department of Chemistry
      Loughborough, England, United Kingdom
  • 1994-1995
    • French National Centre for Scientific Research
      • Institut de recherches sur la catalyse et l`environment de Lyon (IRCELYON)
      Lutetia Parisorum, Île-de-France, France
    • University of Dundee
      Dundee, Scotland, United Kingdom