Carbon dioxide reduction with hydrogen in a continuous catalytic monolith photoreactor

Abstract

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.