Metal modified TiO2 for CO2 photoreduction in unconventional conditions

CO2 photoreduction, a growing field in green catalysis, shows great potentialities to avoid fossil fuels exploitation and to obtain C-based solar fuels through a sustainable process using water as a reductant and light irradiation as only energy input [1]. However, many efforts need to be made to have a substantial breakthrough to increase the efficiency of the whole process. To pursue this aim, different strategies can be followed, such as reaction conditions implementation and photocatalyst formulation. Process efficiency is strictly dependent on chosen photocatalytic materials. In particular titanium dioxide, the most commonly used material, needs to be modified in order to boost light harvesting and increase photoactivity [2]. In this work, TiO2 was modified in order to increase electron mobility on photocatalytic surface. In particular, copper oxide was introduced as a co-catalyst and gold nanoparticles as surface plasmonic agents. Some of the authors reported that unconventional conditions are able to increase solar fuels production from CO2 photoreduction in liquid phase, enhancing in particular CO2 absorption in aqueous media and tuning selectivity to desired products [3]. A novel pressurized liquid phase reactor was employed to study photocatalytic activity of these materials in liquid phase and reaction conditions were chosen in order to enhance CO2 absorption in liquid phase. In photocatalytic tests it was observed the formation of different liquid and gaseous products such as formic acid, formaldehyde, methanol, methane and hydrogen. The different materials provide a significant difference in both activity and product distribution. Photocatalytic behaviours were correlated to different physicochemical properties that were investigated though several techniques.   References [1] O. Ola, M. Maroto-Valer, Journal of Photochemistry and Photobiology C: Photochemistry Reviews 24 (2015) 16-42 [2] A. Olivo, V. Trevisan, E. Ghedini, F. Pinna, C.L. Bianchi, A. Naldoni, M. Signoretto, Journal of CO2 Utilization 12 (2015) 86-94 [3] I. Rossetti, A. Villa, M. Compagnoni, L. Prati, G. Ramis, C. Pirola, C.L. Bianchi, W: Wang, D. Wang, Catalysis Science and Technology 5 (2015) 4481 - 4487