One-Step Hydrothermal Synthesis of Precious Metal-Doped Titanium Dioxide–Graphene Oxide Composites for Photocatalytic Conversion of CO<inf>2</inf> to Ethanol

Abstract

We utilized a one-step hydrothermal process for the synthesis of precious metal-doped titanium dioxide (TiO2)/graphene oxide (GO) composites. The metal-doped TiO2/GO composites, including silver–TiO2/GO (Ag–TiO2/GO), palladium–TiO2/GO (Pd–TiO2/GO), and copper–TiO2/GO (Cu–TiO2/GO), were synthesized by mixing a metal precursor, titanium butoxide, and graphene oxide in a water–ethanol mixture in an autoclave hydrothermal reactor. The photocatalytic performance of the composites was tested in the photoreduction of carbon dioxide (CO2) to ethanol. Ag–TiO2/GO, Pd–TiO2/GO, and Cu–TiO2/GO exhibited an ethanol production rate of 109, 125, and 233 μmol/gcat h, respectively. The outstanding performances of Cu–TiO2/GO can be attributed to a combined effect of key parameters, including optical band gap, crystallite size, and BET surface area.