Photo-driven selective CO2 reduction by H2O into ethanol over Pd/Mn–TiO2: suitable synergistic effect between Pd and Mn sites

Abstract

In this work, CO₂ and H₂O were converted into C₁–C₂ over a Pd/Mn–TiO₂ catalyst under a particular condition (heat, pressure, and illumination). It was found that only C₁ was produced over Pd/Mn–TiO₂ in thermal and pressure fields (180 °C and 3.5 MPa), but C₂ (alcohol) was formed as a major product with the introduction of UV light. Based on the investigation results, it is proposed that the synergism between the Pd–Mn and TiO₂ sites would be responsible for the alcohol product, where Mn acted as a reaction site for CO₂ activation and C–C coupling to form C₂ products. In addition, Pd mainly served as an electron collector that captured the light-excited electrons from TiO₂ and transported them into Mn sites, resulting in a triggered C–C coupling at the given conditions. This study may provide a reliable approach for the conversion of CO₂ into high-value chemicals.