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dc.contributor.authorAltman, E. I.en_US
dc.contributor.authorBaykara, M. Z.en_US
dc.contributor.authorSchwarz, U. D.en_US
dc.date.accessioned2016-02-08T09:39:24Z
dc.date.available2016-02-08T09:39:24Z
dc.date.issued2015en_US
dc.identifier.issn0001-4842
dc.identifier.urihttp://hdl.handle.net/11693/21003
dc.description.abstractConspectusAlthough atomic force microscopy (AFM) was rapidly adopted as a routine surface imaging apparatus after its introduction in 1986, it has not been widely used in catalysis research. The reason is that common AFM operating modes do not provide the atomic resolution required to follow catalytic processes; rather the more complex noncontact (NC) mode is needed. Thus, scanning tunneling microscopy has been the principal tool for atomic scale catalysis research. In this Account, recent developments in NC-AFM will be presented that offer significant advantages for gaining a complete atomic level view of catalysis.The main advantage of NC-AFM is that the image contrast is due to the very short-range chemical forces that are of interest in catalysis. This motivated our development of 3D-AFM, a method that yields quantitative atomic resolution images of the potential energy surfaces that govern how molecules approach, stick, diffuse, and rebound from surfaces. A variation of 3D-AFM allows the determination of forces required to push atoms and molecules on surfaces, from which diffusion barriers and variations in adsorption strength may be obtained. Pushing molecules towards each other provides access to intermolecular interaction between reaction partners. Following reaction, NC-AFM with CO-terminated tips yields textbook images of intramolecular structure that can be used to identify reaction intermediates and products.Because NC-AFM and STM contrast mechanisms are distinct, combining the two methods can produce unique insight. It is demonstrated for surface-oxidized Cu(100) that simultaneous 3D-AFM/STM yields resolution of both the Cu and O atoms. Moreover, atomic defects in the Cu sublattice lead to variations in the reactivity of the neighboring O atoms. It is shown that NC-AFM also allows a straightforward imaging of work function variations which has been used to identify defect charge states on catalytic surfaces and to map charge transfer within an individual molecule.These advances highlight the potential for NC-AFM-based methods to become the cornerstone upon which a quantitative atomic scale view of each step of a catalytic process may be gained. Realizing this potential will rely on two breakthroughs: (1) development of robust methods for tip functionalization and (2) simplification of NC-AFM instrumentation and control schemes. Quartz force sensors may offer paths forward in both cases. They allow any material with an atomic asperity to be used as a tip, opening the door to a wide range of surface functionalization chemistry. In addition, they do not suffer from the instabilities that motivated the initial adoption of complex control strategies that are still used today.en_US
dc.language.isoEnglishen_US
dc.source.titleAccounts of Chemical Researchen_US
dc.relation.isversionofhttp://dx.doi.org/10.1021/acs.accounts.5b00166en_US
dc.subjectAtomicen_US
dc.subjectForceen_US
dc.subjectMicroscopy (AFM)en_US
dc.titleNoncontact atomic force microscopy: an emerging tool for fundamental catalysis researchen_US
dc.typeArticleen_US
dc.departmentDepartment of Mechanical Engineeringen_US
dc.departmentInstitute of Materials Science and Nanotechnology (UNAM)en_US
dc.citation.spage2640en_US
dc.citation.epage2648en_US
dc.citation.volumeNumber48en_US
dc.citation.issueNumber9en_US
dc.identifier.doi10.1021/acs.accounts.5b00166en_US
dc.publisherAmerican Chemical Societyen_US


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