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The Taylor Conferences are organised by theSurface Reactivity and Catalysis (SURCAT) Groupof the Royal Society of Chemistry in the U.K. (1).The series began in 1996, to provide a forum fordiscussion of the current issues in heterogeneouscatalysis and, equally importantly, to promoteinterest in this field among recent graduates. Thefourth in the series was held at Cardiff Universityin the U.K. from 22nd to 25th June 2009, attract-ing 120 delegates, mainly from U.K. academiccentres specialising in catalysis. Abstracts of all lec-tures given at the conference are available on theconference website (2). The first half of the confer-ence consisted of presentations by establishedresearchers from the U.K., Japan and the U.S.A.,with each presentation afforded ample time fordebate and discussion. The format of the secondhalf was similar, but with a key difference: the pre-senters were some of the postgraduate studentsand postdoctoral researchers who, it is hoped, willbecome the future generation of catalysis experts.

Concepts, Theories and MethodologyProfessor Sir Hugh Taylor, after whom the

Taylor conferences are named, was a pioneer inthe study of chemisorption and catalysis on metalsand metal oxides (3). As Professor Frank Stone(Emeritus Professor of Chemistry, University ofBath, U.K.) reminded us in his opening address, H. S. Taylor (as he was known in his time) wasresponsible for introducing the concepts of acti-vated adsorption and of the active site, both ofwhich were highly controversial when he first proposed them around 1930 (4), but which havebecome fundamental to our understanding ofmany catalytic phenomena.

Professor Gabor Somorjai (University ofCalifornia, Berkeley, U.S.A.) developed the themethat progress in catalysis is stimulated by revolu-tionary changes in thinking. He predicted that,whereas in previous eras new catalysts were identi-fied through an Edisonian approach (based on trialand error) or discovered on the basis of empiricalunderstanding, future catalyst design will be basedon the principles of nanoscience. He highlighted hisidea of ‘hot electrons’ that are ejected from a metalby the heat of reaction produced at active sites, butwhich could become a potential energy source ifthey were generated by the absorption of light.

As described by Professor Richard Catlow(University College London, U.K.) and StephenJenkins (University of Cambridge, U.K.), quantummechanical techniques for modelling many-electron systems lend themselves to the study ofcatalytic materials and catalytic reaction pathways.Professor Catlow’s particular expertise lies in thestudy of defective metal oxides, and the way inwhich they interact with metal particles. In the caseof palladium deposited on ceria, his models predictan increase in the concentration of Ce3+ speciesresulting from electron transfer from the metal tothe metal oxide. Jenkins has been examining thelikelihood of specific reaction steps taking place onthe surface of supported metal catalysts. For bothalkane synthesis and combustion, his calculationsimplicate a common formyl intermediate, which isnot readily detected by spectroscopic techniques.However, Professor Charles Campbell (Universityof Washington, U.S.A.) cautioned against an over-reliance on surface modelling. Based on classicalmicrocalorimetric measurements, he has shownthat density functional theory (DFT) underpredicts

Platinum Metals Rev., 2009, 53, (4), 221–225

The Taylor Conference 2009CONVERGENCE BETWEEN RESEARCH AND INNOVATION IN CATALYSIS

Reviewed by S. E. Golunski§ and A. P. E. York*‡

Johnson Matthey Technology Centre, Blounts Court, Sonning Common, Reading RG4 9NH, U.K.;

and ‡Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street,

Cambridge CB2 3RA, U.K.; *E-mail: ayork@matthey.com

DOI: 10.1595/147106709X474307

§Present address: Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.

the heat of adsorption for a variety of molecules(for example, carbon monoxide, cyclohexene andaromatics) on a range of surfaces (such as carbon,precious metals or metal oxides).

Taking a View Professor Lynn Gladden (University of

Cambridge) described how macroscopic andmicroscopic events can be tracked in an opticallyopaque system, such as a catalytic reactor. Usingmagnetic resonance imaging (MRI) – essentially thesame technique as used diagnostically in medicine –she has been able to observe the liquid flow fieldsthat develop in packed bed reactors. By combiningthe images with measurements from temperaturesensors, detailed reaction profiles can be producedfor steady-state and dynamic operating conditions.

On a different scale, Professor Chris Kiely(Lehigh University, U.S.A.) has used dark-fieldimaging techniques to detect the smallest metallic,bimetallic and metal oxide particles (less than 1 nmin diameter) by electron microscopy. In what maybecome a seminal study, he has correlated the highCO-oxidation activity of a specific gold/iron oxide(Au/Fe2O3) catalyst with the presence of two-layer, 0.5 nm-diameter gold clusters.

The importance of studying catalysis over arange of scales was emphasised by ProfessorTrevor Rayment (Diamond Light Source Ltd,U.K.). The new U.K. synchrotron light source isintended to provide understanding of ‘real catalysts, under real conditions, in real time’ (5).One of the ambitions is to increase the through-put for techniques such as X-ray absorptionspectroscopy, by reducing the amount of non-productive beam time. Although the Diamondfacilities are not expected to provide the tools forcatalyst discovery, it is hoped that they can accel-erate the development process by identifying thecritical relationships between catalyst structureand performance.

Controlling SelectivityStressing a point made by Professor Somorjai

that catalysis in the 21st century is all about selec-tivity, Chris Baddeley (University of St Andrews,U.K.) and Professor Andrew Gellman (Carnegie

Mellon University, U.S.A.) separately describedthe complex dependence of enantioselective reac-tions on surface composition and structure. As explained by Professor James Anderson(University of Aberdeen, U.K.), in the context ofalkyne hydrogenation, poor selectivity is often theresult of heterogeneity in the exposed sites, evenon apparently clean and compositionally homoge-neous surfaces. Through targeted use of additives,such as bismuth in the case of palladium-basedhydrogenation catalysts, specific non-selectivesites can be deliberately blocked.

During the direct synthesis of hydrogen perox-ide from hydrogen and oxygen, the combustion ofhydrogen and the over-hydrogenation of hydrogenperoxide to water need to be suppressed.Professor Graham Hutchings (Cardiff University,U.K.) has shown that gold-palladium catalysts areamong the most effective, but their performancecan be sensitive to the support material used. Incollaboration with Professor Kiely, he has foundthat the nature of the dispersed gold-palladium canvary, with core-shell particles (on titania and alumina) producing lower yields of H2O2 than palladium-rich alloy particles (on carbon). Bothtypes of core-shell particle, those with a gold coreand palladium shell and those with a palladium coreand gold shell, were less active than the palladium-gold alloy.

Professor Masatake Haruta (Tokyo Metropoli-tan University, Japan) has found that small goldclusters can selectively catalyse some particularlychallenging reactions. The outstanding example isthe selective insertion of oxygen into propylene toform propylene oxide, which is currently producedby indirect processes that produce large quantitiesof waste byproducts. By reactively grinding a non-chloride Au(III) precursor with titanium silicalite(TS-1), Professor Haruta has dispersed the gold as1.6 nm particles, which can activate propylene toreact with O–O–H species formed from oxygenand water at the metal-support interface.

Promoting and Maintaining ActivityVanadia supported on θ-alumina is one of the

best catalysts for butane dehydrogenation, but therate of reaction is very sensitive to the vanadia

Platinum Metals Rev., 2009, 53, (4) 222

loading. Professor David Jackson (University ofGlasgow, U.K.) reported that maximum activitycoincides with the presence of a mainly polymericform of vanadate species which covers most of thealumina surface. However, another key perfor-mance criterion is durability. During butanedehydrogenation, two forms of deactivation canbe discerned: a short-term but reversible effectcaused by deposition of carbon-rich species onthe catalyst surface, and a longer-term effect asso-ciated with an irreversible phase change in thealumina.

In the Francois Gault Lecture, ProfessorRobbie Burch (Queen’s University Belfast, U.K.)explained the challenges faced in developing andstudying catalyst technology for removing nitro-gen oxides (NOx) from diesel exhaust. Focusingon the use of silver for NOx reduction by directreaction with some of the diesel fuel, he showedthat its performance can be dramatically improvedby the addition of hydrogen. As described in a presentation by Stan Golunski (Johnson MattheyTechnology Centre, Sonning Common, U.K.) thehydrogen can be generated in situ through aprocess of exhaust gas reforming using a rhodiumcatalyst. Professor Burch explained how X-rayabsorption fine structure (EXAFS) studies of silver have been used to refute one of the pro-posed roles of hydrogen, as a structural modifier,implying instead that it is directly involved in theNOx-reduction mechanism. Although severalspectroscopic studies have been published (6)showing the presence of cyanide and isocyanateon the silver surface when hydrogen is present,kinetic measurements at Queen’s University Belfasthave ruled these out as reactive intermediates, suggesting that more transitory species (such ashydroxamic acid or ammonia) are involved.

Future ProspectsDuring his introduction to the postgraduate

student and postdoctoral researcher presentations,Jack Frost (Johnson Matthey Fuel Cells, U.K.)compared and contrasted the academic process ofresearch with the industrial activity of innovation.He used the example of vehicle emission controlto show how the pressing need for improved local

air quality led to the development of technologyfor catalytic aftertreatment using pgm catalysts (7).This highly effective technology does not, howev-er, address the global problem of greenhouse gasemissions, which is now the prime motivator forthe introduction of fuel cells.

Appropriately, there was an environmentaltheme running through many of the presentationsin this section of the conference. For example, COoxidation was covered by SankaranarayananNagarajan (National Chemical Laboratory, Pune,India), who looked at oxygen mobility and the roleof subsurface oxygen on palladium surfaces (8, 9),Figure 1. The subject was also covered by KevinMorgan (Queen’s University Belfast), who present-ed a temporal analysis of products (TAP) studyshowing that the addition of gold to CuMnOxresults in the availability of more surface oxygenand promotion of the Mars-van Krevelen oxygentransfer mechanism.

A number of researchers from CardiffUniversity presented work on selective oxidationreactions. For example, Jonathan Counsell has beenstudying the effect of adding gold to a supportedpalladium acetoxylation catalyst. He has foundthat the gold suppresses carbon formation on thepalladium surface by preventing dehydrogenation.Kara Howard described her work on modellingoxygen dissociation on gold clusters supported on iron oxide, and showed that the iron oxide stabilises dissociated oxygen atoms. DyfanEdwards presented a surface science study of thesynergy between the individual metal oxides iniron molybdate catalysts, which are used for oxi-dising methanol to formaldehyde. The selectivityof iron oxide changes with the level of coverageby molybdenum, from total combustion when nomolybdenum is present, to partial oxidation (toCO) at low coverage, and finally selective oxida-tion (via a methoxy intermediate) at high coverage.Dr Jennifer Edwards has been examining theeffect of preparation and pretreatment variableson the performance of gold-palladium catalystsfor the direct synthesis of hydrogen peroxide.Acid pretreatment of the support material hasresulted in catalysts with lower activity for theunwanted consecutive hydrogen peroxide-hydro-

Platinum Metals Rev., 2009, 53, (4) 223

genation reaction, leading to very impressivehydrogen peroxide yields.

The influence of the iron:cobalt ratio in anFe2O3-Co3O4 catalyst, for converting ethanol tohydrogen, has been studied by Abel Abdelkader(Queen’s University Belfast). Fe2O3 catalysesethanol steam reforming, and Co3O4 the water-gasshift reaction, so that a 1:1 ratio produces the opti-mum yield. In the field of syngas and hydrogenutilisation, Poobalasuntharam Iyngaran (Universityof Cambridge) presented a study of the effect ofpotassium promoters on ammonia synthesis overiron, which showed that stepwise hydrogenationof nitrogen surface adatoms is unaffected by thepresence of potassium. Sharon Booyens (CardiffUniversity) is interested in DFT modelling of COadsorption on iron surfaces, in the context ofFischer-Tropsch catalysis. The models predictthat surface carbon causes a weakening of theFe–CO interaction, and therefore CO dissociationbecomes less favourable. Andrew McFarlane(University of Glasgow) presented his work on C5 olefin hydrogenation over 1% Pd/Al2O3. Hesuggested that reaction of the cis-pentene isomermust proceed via formation of the trans isomerbefore hydrogenation can occur.

Finally, there were several very topical presenta-tions concerned with clean synthesis of chemicalsand fuels. Lee Dingwall (University of York, U.K.)has been synthesising and working with a bifunc-tional heterogeneous catalyst that combines anactive ruthenium organometallic centre with apolyoxometallate cage, Figure 2. This provides acidsites and also confers great stability, and the cata-lyst structure displays high activity for C–C bondformation. Ceri Hammond (Cardiff University)described the reaction of glycerol with urea overzinc, gallium or gold supported on zeolite.Glycerol carbonate can be obtained with highselectivity in a one-step solvent-free process overthese catalysts, though there is some question overtheir stability.

The prize for the best student presentation wasawarded to Janine Montero (University of York)who is researching the use of heterogeneous catalysts for biodiesel synthesis by transesterifica-tion, as a replacement for the liquid catalystscurrently in use. She has shown, by Auger electronspectroscopy, that high-temperature calcination of nanoparticulate magnesium oxide results inincreased surface polarisability, and therefore higherLewis basicity. Her results show that there is a

Platinum Metals Rev., 2009, 53, (4) 224

Fig. 1 Schematic model for oxygen diffusion followed by CO + O2 reaction on Pd(111) > 550 K. Pdδ+= mildly oxidised Pd(Courtesy of Chinnakonda S. Gopinath, National Chemical Laboratory, Pune, India)

CO

O2

4

6

2

CO2

1

5

3

Pd(111)

Pdδδ+(111)

Pdδδ+(111)

Pd(111)

Pdδδ+(111)

Pdδδ+(111)

linear relationship between polarisability and trans-esterification activity over these MgO catalysts.

SummaryIn summing up the conference, Professor

Wyn Roberts (Emeritus Professor, CardiffUniversity) recalled that when he began his Ph.D.he had to make the choice between studyingclean surfaces (i.e. single crystals) or real catalysts.As many of the presentations highlighted, thisdistinction is no longer useful, with the so-called‘material’ and ‘pressure’ gaps in catalysis, betweenresults obtained from surface science studies,usually using idealised surfaces under high

vacuum, and those from real catalyst materials atambient or high pressures (10), having graduallynarrowed. Frost had earlier commented on a sim-ilar convergence, between research andinnovation. As he pointed out, though, theseactivities need to remain distinct, because theyfulfil quite different functions. However, withtheir shared values of insight, integrity, creativityand professionalism, they will be increasinglydirected in parallel at our most urgent challengesin catalysis and in society: sustainability and envi-ronmental protection.

The fifth Taylor Conference is scheduled totake place in Aberdeen in 2013 (11).

Platinum Metals Rev., 2009, 53, (4) 225

+ -

HNEt 3

HNEt3

P

Ru C

P

WO

Fig. 2 Proposed structure of thepolyoxometallate-tethered rutheniumcomplex [HNEt3]+[(Ru{η5-C5H5}{PPh3}2)2(PW12O40)]–(Courtesy of Karen Wilson, University ofYork, U.K.)

1 Royal Society of Chemistry, Surface Reactivity andCatalysis (SURCAT) Group: http://www.rsc.org/Membership/Networking/InterestGroups/SurfaceReactivity/index.asp (Accessed on 5th August 2009)

2 The Taylor Conference 2009: http://www.taylor.cf.ac.uk/ (Accessed on 5th August 2009)

3 E. R. Rideal and H. S. Taylor, “Catalysis in Theory andPractice”, Macmillan and Co Ltd, London, U.K., 1919

4 P. B. Weisz, Microporous Mesoporous Mater., 2000, 35–36,1

5 Diamond Light Source, Publications, Case Studies:http://www.diamond.ac.uk/Home/Publications/case_studies.html (Accessed on 27th August 2009)

6 F. Thibault-Starzyk, E. Seguin, S. Thomas, M. Daturi,H. Arnolds and D. A. King, Science, 2009, 324, (5930),1048

7 M. V. Twigg, Appl. Catal. B: Environ., 2007, 70, (1–4),2

8 C. S. Gopinath, K. Thirunavukkarasu and S. Nagarajan,Chem. Asian J., 2009, 4, (1), 74

9 S. Nagarajan, K. Thirunavukkarasu and C. S. Gopinath,J. Phys. Chem. C, 2009, 113, (17), 7385

10 J. M. Thomas, J. Chem. Phys., 2008, 128, (18), 18250211 Royal Society of Chemistry, Publishing, Journals,

PCCP, News, 2009: http://www.rsc.org/Publishing/Journals/CP/News/2009/TaylorPCCPPrizes.asp(Accessed on 5th August 2009)

Stan Golunski has recently been appointedDeputy Director of the Cardiff CatalysisInstitute; he was formerly TechnologyManager of Gas Phase Catalysis at theJohnson Matthey Technology Centre atSonning Common in the U.K. His researchinterests include catalytic aftertreatmentand reforming.

References

Andy York is a Johnson Matthey ResearchFellow in the Department of ChemicalEngineering and Biotechnology at theUniversity of Cambridge, U.K. Hisresearch interests lie at the interfacebetween catalyst chemistry and reactionengineering.

The Reviewers