Photocatalytic reduction of carbon dioxide to methanol using nickel-loaded TiO2 supported on activated carbon fiber

Abstract

A nanocomposite (NC) of nickel-loaded TiO2 photocatalysts was immobilized on activated carbon fibers (ACFs) to provide a highly illuminated surface area of catalyst for the photocatalytic reduction of CO2 with H2O to methanol under UV and visible light irradiation. The incorporation of nickel in the TiO2 texture inhibited the grain growth of anatase crystallites and suppressed phase transformation. The Ni+2 atoms replaced some of the Ti atoms in the crystal lattice of TiO2 during the sol–gel method, thus changing the optical absorption. The ACF support clearly decreased the recombination of photo-generated electron–hole pairs, thus promoting the photocatalytic activity of nickel-loaded TiO2. From the results, the methanol yield in 2h over NiO–TiO2/ACF was 755.1μmol.g−1 and 986.3μmolg−1 under UV and visible light irradiation, respectively. The NiO–TiO2/ACF NC was also easily separated from the reaction medium for regeneration and showed good stability after multiple uses. A possible photocatalytic mechanism was proposed which is beneficial for further improving the photocatalytic reduction of CO2 to methanol fuel.