Weak Metal-Support Interaction Boosting H ₂ Activation over CuFeAl-LDH-Derived Photothermocatalysts for Enhanced Reverse Water−Gas Shift Reaction

The photothermocatalytic reverse water−gas shift (RWGS) reaction converts carbon dioxide (CO 2 ) into carbon monoxide (CO), a key component of synthesis gas for Fischer−Tropsch synthesis (FTS). Previous studies on copper (Cu)-based catalysts have demonstrated that the active metals played a key role in improving performance, while the effect of metal-support interactions on catalytic activity has been underexplored. Herein, the interaction between Cu and alumina (Al 2 O 3 ) was precisely regulated by doping iron species (Fe x + ) into the support structure via a reductive treatment on the layered double hydroxide (LDH) to fabricate metal/metal oxide catalyst. The optimized Fe-doped catalyst (Cu 10 Fe 1 Al 4 ) showed a weak metal-support interaction, which delivered a 28.5% CO 2 conversion with a 99.9% selectivity for CO at photothermal 280 °C, 2.7 times as that of bare Cu-based catalyst (Cu 10 Al 4 ). Various mechanism characterizations revealed that the improved performance was related with the weak metal-support interaction. This interaction was conducive to the reduction of the LDH precursor and the dispersion of the resulting Cu nanoparticles (NPs). Consequently, it led to the formation of more metallic Cu active sites, promoting the adsorption and activation of H 2 and the redox process in the RWGS reaction. Building on prior studies, this work demonstrated that H 2 adsorption and activation, rather than CO 2 adsorption, predominantly governed the catalytic performance in the RWGS reaction. Furthermore, the proposed strategies on the metal-support interaction regulation can provide guidelines for design of nanocatalysts.