Hydrothermally Synthesizing Nanospheres of Pd Loaded TiO₂ for Photocatalytically Reducing CO₂ in Isopropanol to Isopropyl Formate

Abstract

Photocatalytic reduction of CO₂ was carried out on villiform spherical catalysts of Pd-TiO₂ in isopropanol solution. The catalysts were synthesized by hydrothermal method, their structures, morphologies and optical absorption properties were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis absorption spectroscopy (UV-vis). The photocatalytic activities with different loading amounts and morphologies were evaluated for determining the dominant effect and optimizing the catalyst preparation. Based on a villiform spherical TiO₂ with the largest specific surface area in our experiments, we prepared a set of catalysts with various loading amounts of palladium and tested them by bubbling CO₂ through the slurry of catalyst and isopropanol. The highest formation rate of isopropyl formate was 276.6 μmol/g·cat/h. Eventually we proposed the reaction mechanism.

Keywords

photocatalytic reduction of CO₂ / Pd-TiO₂ / isopropanol / hydrothermal method / isopropyl formate

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