Perhaps the most difficult surface-science challenge is to monitor reaction pathways and kinetics at sliding solid-solid interfaces. Strategies for measuring reaction pathways and their kinetics for well-defined surfaces in ultrahigh vacuum (UHV) are described using the example of sliding-induced decomposition of adsorbed methyl thiolate species, formed by exposure to dimethyl disulfide, on copper. Two stress-activated elementary-step reactions are identified. The first is the mechanochemical decomposition of adsorbed methyl thiolate species, that form rapidly by dimethyl disulfide reacting with copper, to form gas-phase hydrocarbons and chemisorbed sulfur. In a second stress-induced reaction, surface sulfur is transported into the subsurface region of the copper. This process causes an increase in oxidation state of copper, and the creation of vacant surface sites that allows the tribochemical reaction cycle to continue.<br/> <br/>The mechanism of shear-induced methyl thiolate decomposition is investigated theoretically using first-principles quantum calculations to obtain an estimate of the value of the activation volume. The results are compared with those for the rate of stress-induced decomposition of methyl thiolate species on a Cu(100) single crystal substrate measured by atomic force microscopy in ultrahigh vacuum.<br/>

Understanding mechanocatalytic reaction pathways: Surface chemistry at the solid-solid interface

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.