Optimization of photocatalytic fuel production via material design

The increasing concentration of atmospheric CO2, largely driven by anthropogenic emissions like fossil fuels consumption, is a major contributor to climate change and global warming. A possible strategy to reduce its concentration in the atmosphere consists in the catalytic conversion of CO2 into valuable products such as fuels. Amongst various processes, CO2 photoreduction using solar light represents a promising approach for a more sustainable fuel production. In this study, two different strategies were explored to improve the photocatalytic activity under UV and visible light of two different materials, commercial titanium dioxide P25 and an alternative material, perovskite BaTiO3, whose synthesis was also optimized for this work. The first approach involved nitrogen doping to narrow the materials band gaps and enhance their visible light absorption. The second method employed the deposition via incipient wetness impregnation of -Fe2O3, NiO and CuO nanoparticles on different TiO2 and BaTiO3 samples as co-catalysts, aimed at enhancing charge separation and catalytic activity of the photocatalysts. The materials’ composition and properties were characterized using elemental analysis, high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). Photocatalytic activity was tested for CO2 reduction under UV radiation (40 W/m2) and simulated standard solar illumination (AM 1.5G). Among the tested materials, NiO-TiO2 showed the highest activity, both for methane and hydrogen production.