Dynamic Modulation of Metal–Support Coupling Drives Photothermal Reverse Water–Gas Shift Reaction on Cobalt–Carbon Interfaces

Abstract Photothermal catalysis has emerged as a promising route for CO2 conversion; however, whether light serves as a heat source or actively modulates catalytic active sites remains an open question. This work reports a defect-enhanced metal–carbon interaction strategy for tuning the electronic structure of cobalt species supported on carbon nanotubes (CNTs), enabling a highly selective reverse water–gas shift (RWGS) reaction to CO through light-induced electronic and adsorption modulation. Among catalysts with different cobalt nanoparticle sizes, 3Co/CNTs shows the highest photothermal catalytic performance, delivering a CO production rate of 299.3 mmol gcat–1 h–1 (10.0 mol gCo–1 h–1) and a CO selectivity of 98%, substantially outperforming both lower and higher Co loadings and showing a clear advantage over thermal catalysis at identical temperatures. Wavelength-dependent activity and a reduced apparent activation energy under irradiation confirm a non-thermal light effect. Spectroscopic analyses, including XPS, EPR, and in situ DRIFTs, together with CO2-TPD and H2-TPD measurements, reveal that light irradiation induces charge redistribution at the defect-cobalt interface and dynamically modulates CO2 and H2 adsorption. Density functional theory calculations further demonstrate that light-induced upshifting of the Co d-band center enhances adsorbate-metal interactions, providing an electronic basis for the observed photothermal enhancement. These findings establish dynamic modulation of metal-support electronic coupling and adsorption energetics as a key mechanism for photothermal CO2 reduction, offering a general strategy for designing light-responsive catalytic interfaces.