Direct Photocatalytic CO2 Reduction in Rich Amine for Formic Acid Production

Abstract

Direct CO₂ reduction from rich amine is advantageous as this allows for a push a step closer to realising the concept of integrated carbon capture and utilization. This study looks into the application of using a photocatalytic process to convert the absorbed CO₂ into formic acid. A slurry system using TiO₂ as a photocatalyst was used together with a Ultraviolet C (UVC) light source and based on Response Surface Methodology (RSM) analysis, with the empirical model R² of 0.9080 achieved, the optimum yield of formic acid obtained was 108 µmol/g cat·hr when running with 0.2 g TiO₂, at 50 ℃ and a 3-hour operation. The yield of product obtained is comparable to others reported in the literature. A moderate kinetic model fit was achieved for formic acid production with an R² of 0.64 and Root Mean Squared Deviation (RMSD) of 14.08. Comparison is done between slurry and immobilised TiO₂ where a 33% drop in yield was achieved when the photocatalyst was immobilised onto Polytetrafluoroethylene (PTFE) fibres.