Carbon dioxide reduction with hydrogen in a continuous catalytic monolith photoreactor

Photocatalytic CO₂ reduction with H₂ as a reductant over gold (Au)-doped TiO₂ nanocatalysts in a continuous monolith photoreactor has been investigated. The nanocatalysts were characterized by XRD, SEM, N2 adsorption-desorption and UV-Visible spectroscopy. Crystalline nanoparticles of anatase phase TiO₂ were obtained in the Au-doped TiO₂ samples. CO was the major product over 0.5 wt. % Au-doped TiO₂ with the yield rate of 12,305 ppm g-catal.^-1 h^-1, 318 times higher than un-doped TiO₂ catalyst. Significantly higher photoactivity of Au-doped TiO₂ was obviously due to fast electron transfer with hindered recombination rates and larger illuminated surface area inside the monolith channels. The CO production rate was gradually reduced with increasing the space velocity. The stability of the reused catalysts for CO production sustained at cyclic runs. It is evident Au-doped TiO₂ nanocatalyst supported over monolith channels is highly potential for continuous CO₂ photoreduction to CO and hydrocarbons.