Photothermal CO 2 and H 2 O Reduction via Pulsed Near‐IR Activation of Transition Metals

ABSTRACT Pulsed near‐infrared (NIR) irradiation offers a powerful nonequilibrium route for activating catalytic transformations on metal surfaces through ultrafast photothermal heating. Here, we demonstrate that 1064 nm nanosecond pulses drive bias‐free H 2 generation and CO 2 conversion on bare transition‐metal foils without engineered plasmonic nanostructures or semiconductor absorbers. In water, interfacial photothermal heating promotes efficient H 2 evolution, whereas in wet CO 2 atmospheres the same pulses produce CO together with Fischer−Tropsch‐like C 2 −C 7 hydrocarbons via thermally generated *H and *CO intermediates. Simulations show that each pulse generates confined, ultrafast thermal excursions that transiently exceed the activation thresholds for H 2 O dissociation and CO 2 activation, thereby explaining the low apparent barriers for H 2 evolution and the higher barriers associated with CO formation. Across both environments, laser power and repetition frequency lead to markedly reduced apparent activation energies relative to steady‐state thermochemical values, reflecting ultrafast localized heating, incomplete inter‐pulse cooling, and dynamic surface coverage rather than changes in intrinsic reaction barriers. Overall, this work establishes a scalable photothermal platform requiring no engineered plasmonic nanostructures for solar‐thermal H 2 production and CO 2 upgrading and provides design rules for engineering nonequilibrium photothermal interfaces capable of driving reactions inaccessible under steady‐state operation.