Abstract
<jats:p> Sabatier scaling relationships impose fundamental limits on the performance of heterogeneous catalysis by coupling the energetics of reactant activation, intermediate stabilization, and product desorption. We show that visible photons circumvent this inherent material constraint by selectively removing a rate-limiting surface intermediate without changing the thermal catalytic energy landscape. Using formic acid decomposition on Pt, we demonstrated that 450 nm photon excitation under isothermal conditions reversibly promotes catalytic turnover by more than three orders of magnitude (4000x) beyond the thermal Sabatier-limited maximum while preserving 95% selectivity to dehydrogenation products, at an apparent quantum yield of 40%. Operando infrared spectroscopy showed that visible wavelength photons monotonically depleted linearly adsorbed CO*, the strongly bound intermediate accumulating to high steady-state coverage on account of slow thermal desorption relative to its formation. Across excitation wavelengths, photon-driven rates collapsed onto a single linear dependence on the extent of CO* depletion, identifying photon-promoted CO* desorption as the controlling event. Kinetic H-D isotope exchange experiments further separated the photon-driven and thermal pathways: thermal rates exhibited a primary formyl C–H isotope effect, while photon-driven rates did not, consistent with an isotope-insensitive CO* photodesorption step. With increasing photon flux, apparent formic acid reaction orders increased toward unity and apparent activation barriers decreased from 62 ± 3 kJ mol <jats:sup>-1</jats:sup> toward zero, reflecting a photon-controlled shift from CO*-coverage-dominated kinetics toward turnover governed by the intrinsic rate of formic acid activation. These findings demonstrate that photons break through Sabatier-imposed rate maxima not by modifying adsorption energies, but by selectively shortening the surface residence time of a strongly bound intermediate. This work establishes photon-regulated intermediate lifetimes as a strategy for catalytic performance beyond conventional thermochemical limits. </jats:p>