Friction-induced electrochemical activation of platinum group metals via electromechanical coupling

Platinum group metals (PGMs), long considered chemically inert, exhibit unexpected reactivity at the metal-water interface when subjected to simultaneous friction and electric fields. This tribo-electrochemical coupling unveils a reaction regime fundamentally different from conventional electrochemical or mechanical activation. Here, we demonstrate that friction, coupled with a positive surface potential, drives the rapid formation of submicron oxide layers on platinum surfaces. We propose that friction lowers activation energy barriers and enhances mass transport, thereby accelerating anodic oxidation through a stress-augmented thermally activated mechanism. The resulting nanostructured oxides apparently exhibit higher electrocatalytic activity than that of metallic platinum, offering promising potential for microscale sensors and catalytic microreactors. Notably, this localized oxidation also occurs in other PGMs, indicating a broadly applicable strategy for activating inert metals via electromechanical coupling.