CO2 photocatalytic reduction with CNT/TiO2 based nanocomposites prepared by high-pressure technology

Previous works with titanium dioxide based photocatalysts synthesized with supercritical fluids led to improved catalyst properties in comparison to those prepared by traditional methods, but still insufficient CO2 reduction rates. In this work, in order to upgrade this type of catalysts, two supercritical methods have been used to prepare CNT/TiO2 and CNT/TiO2/Cu nanocomposites. The effect on photocatalytic performance of CNT/Ti-2 ratio and Cu load has been investigated. Decreasing photocatalytic activities were observed when the CNT/TiO2 relationship separated from unit. Regarding the effect of copper doping, it was overshadowed by the effect of CNT support. Finally, because of the excellent properties of CNTs, synthesized composites showed greater catalytic activities than bare TiO2. Specifically, the catalyst with largest activity led to CO and CH4 production rates of 8.1 and 1.1 mu mol g(-1) h(-1), which were much higher than those on P25 (4 times for CO and 15 times for CH4). (C) 2020 Elsevier B.V. All rights reserved.