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Driving and measuring chemical reactions at the nanoscale is crucial for developing safer, more efficient, and environment-friendly reactors and for surface engineering. Quantitative understanding of surface chemical reactions in real operating environments is challenging due to resolution and environmental limitations of existing techniques. Here we report an atomic force microscope technique that can measure reaction kinetics driven at the nanoscale by multiphysical stimuli in an ambient environment. We demonstrate the technique by measuring local reduction of graphene oxide as a function of both temperature and force at the sliding contact. Kinetic parameters measured with this technique reveal alternative reaction pathways of graphene oxide reduction previously unexplored with bulk processing techniques. This technique can be extended to understand and precisely tailor the nanoscale surface chemistry of any two-dimensional material in response to a wide range of external, multiphysical stimuli.

Electrochemical reactions are a critical class of processes strongly influenced by atomic scale effects, where the relationships between local chemical composition, stress, strain, and reactivity are not well understood. Here we investigate the relationship between applied stress and reaction rates for the oxygen evolution reaction on multi-layered graphene using conductive atomic force microscopy. During the reaction, oxygen groups accumulate on the surface and the oxygenation rate increases with applied load. The results also show that the rate is not uniform across the surface, where local edges and defects are more reactive than the basal plane. The results presented here are interpreted in the context of transition state theory, where applied load over the reaction coordinate linearly modifies the energy landscape. This work motivates the general efficacy of atomic force microscopy as a tool to study relationships between local mechanical surface effects and electrochemical reactivity.

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