Feasibility Study of the Solar-Promoted Photoreduction of CO2 to Liquid Fuels with Direct or Indirect Use of Renewable Energy Sources

Solar irradiation data collected at the latitude of Milan city, near 45th parallel North, and original activity some high-performing photocatalysts (i.e., commercial TiO2 P25, prepared by flame spray pyrolysis, 0.2% wt/wt Au/P25) have been used to evaluate feasibility efficiency an ideal solar photoreactor for CO2 photoreduction in liquid phase. The best theoretical performance was achieved with bare P25 titania, despite fact that it material widest band gap (3.41 eV vs. 3.31 FSP 3.12 Au/P25). In case energy storage calculated as about 2% (considering total irradiated energy) ca 18% only UV fraction irradiance). Most content products stored formic acid, which would return a productivity 640 kg/year kgcat under daylight considering variance irradiance data. Bare titania gave less promising result, while Au/P25 ranked middle. A comparison between proposed setup lamps powered through wind turbine or panels, allow indirect use renewable sources also intended purposes, unveil latter is many times efficient than hypothesized direct photoreactor, could be reasonable system production peaks.