A Study of the Reaction Kinetics and Solar Concentrator-Based Reactor Design for Photocatalytic Conversion of CO2 Into Fuel

Abstract

Solar powered conversion of CO₂ into fuel and other value-added chemicals is considered a holy grail toward a sustainable future. Development of materials that can catalytically convert CO₂ and water vapor into hydrocarbons under sunlight has been one of the most formidable challenges in the 21st century. This study have recently demonstrates that by introducing hydrophilic and hydrophobic sites on nanostructured TiO₂-reduced graphene oxide nanocomposite surfaces, yield of methane from photoreduction of CO₂ can be enhanced by ≈30%. Here this study reports the study of reaction kinetics for TiO₂-rGO photocatalysts through pressure and temperature dependent measurements of the product yield. By applying the Langmuir–Hinshelwood model on the pressure dependent CO₂ conversion data, the reaction rates are calculated for selective adsorption of CO₂ and H₂O on the photocatalyst surface. These data are correlated with charge transport studies done through current-voltage (I–V) characteristics of the photocatalyst measured in presence of CO₂ and H₂O. On the other hand, a unique solar-concentrator based reactor design is developed. Such a prototype allows about a 20 °C rise in the temperature that enhances the rates of photocatalytic reactions. A comparative study of the CO₂ photoreduction experiments in absence and in presence of the concentrated sunlight are presented.