Review A Critical Review of the Electrocatalysis Reported at C 60 Modified Electrodes Sebastian Griese, Dimitrios K. Kampouris, Rashid O. Kadara, Craig E. Banks* Faculty of Science and Engineering, School of Biology, Chemistry and Health Science, Division of Chemistry and Materials, Manchester Metropolitan University, Chester Street,Manchester M1 5GD, Lancs, UK *e-mail: c.banks@mmu.ac.uk Received: March 26, 2008 Accepted: April 22, 2008 Abstract ElectrodesmodifiedwithC 60 havebeenreportedtobeelectrocatalyticforarangeofanalyticaltargets.Inthisreview we critically overview the recent explosion of interest in C 60 modified electrodes. Keywords: C 60 modifiedelectrodes, Electrocatalysis, Catalytic reactions DOI: 10.1002/elan.200804238 1. Introduction Electrochemistsarealwayssearchingforoptimalelectrode surfaces which can offer significant advances. A common waytoachievethisisthroughelectrodemodificationwith the aim of producing electrocatalytic responses. Desirable characteristicsformodifiedelectrodesarethereductionin the overpotential of the analyte under investigation, in- creased stability of the electrode response coupled with incrementsinpeakheightsfacilitatinglowerdetectionlimits and increased specificity compared to the bare underlying electrode. There is an extensive literature on chemically modified electrodes for the electroanalysis of target ana- lyteswhichareultimatelyutilizedtoincreaseselectivityand sensitivity [1–4]. However, common problems of this approachareinstability,lowsensitivity,costandirreprodu- ciblethicknesseswhichmaylimittheirapplications. Inthecontinuedsearchforelectrocatalyticarchitectures, there has been an explosion of modifying electrodes with carbonnanotubesinthesearchforelectrocatalyticrespons- es[5–9].Itiswelldocumentedthatsuchimprovementsare duetotheuniquestructureofthecarbonnanotubeswhere thepresenceofedgeplanelike-sites/defectsaretheoriginof heterogeneouschargetransfer[5,6].Infact,thepresenceof edge plane like-sites/defects are required if any faradaic electrochemical processes are to take place. Recent prob- lems of carbon nanotube modified electrodes have come fromthepresenceofmetallicimpuritiesgivingrisetofalse electrochemicalperformance/interpretation[10–13]. Anotherexamplereportedintheliteratureforachieving electrocatalysis is that of modifying an electrode surface withC 60 fordetectingtargetanalytesinaqueoussolutions. As we will see later, the performance of C 60 modified electrode have been reported to produce electrocatalytic responsescomparedtotheunderlyingelectrodeforcertain target analytes. C 60 appears to be attractive to researchers for modifying electrode surfaces because it is chemically stable,metallicimpurityfree(seelater),andrelativesimple toimplementandgivesrisetoreproducibleelectrocatalytic responses[14].Figure1depictsthestructureofC 60 whichas atruncatedicosahedralstructure,apolygonwith60vertices and32faces,12ofwhicharepentagonaland20hexagonal [15].ThestructureofC 60 iscompletelydifferenttothatof typical sp 2 carbon structures and cannot be discussed in terms of the usual key structural factors such as the intraplanar microcrystallite size (later grain size) and interplanar microcrystallite size (graphite single crystals). TheuniquestructureofC 60 meansthatithasadistinctlack of edge plane like- sites/defects [6, 15]; consequently the originofthereportedelectrocatalysisis,totheauthors,quite curious. In this review we critically and systematically overview therecenttrendofmodifyingcarbonelectrodeswithC 60 in order to achieve electrocatalysis. We also highlight two Fig.1. The structure of C 60 , a polygon with 60 vertices and 32 faces, 12 of which are pentagonal and 20 hexagonal. 1507 Electroanalysis 20, 2008,No.14,1507–1512 # 2008 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim