Ru-Doped UiO-66-Derived ZrO2-Enhanced Photothermal Catalytic CO2 Hydrogenation to Methane

Currently, there is a thermodynamic and kinetic mismatch between carbon dioxide methanation. Carbon dioxide is stable in nature and requires a highly active catalyst to facilitate its reduction reaction. In this article, Ru/ZrO₂ catalysts are prepared by a structure-directed derivatization strategy using zirconium-based metal-organic frameworks (MOFs) (UiO-66) as precursors. The porous framework structure of MOFs was utilized to construct Ru nanoparticles with a large size (≈9.7 nm). Photothermal catalysis is employed, and the photoexcitation induced the transfer of electrons from the conduction band of ZrO₂ to Ru, which elevated the electron density of Ru to the enriched state and promoted the activation of CO₂ adsorption, while the photothermal effect facilitated the warming of the catalyst bureau, which provided a favorable condition for CO₂ methanation. The compositional valence, morphology, specific surface area, bandgap and other properties of the catalysts were evaluated by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscpe, Brunner-Emmet-Teller measurements, hydrogen temperature-programmed reduction, CO₂-TPD, ultraviolet–visible, photoluminescence, and photocurrent response characterization. The experimental results showed that 99% methane selectivity and 120.354 mmol g_cat⁻¹ h⁻¹ methane yield were achieved at 1 MPa and photothermal (250 °C) conditions.