Morphology influence on charge carrier dynamics in photocatalytic CO2 conversion: Comparative analysis between TiO2 nanopowder and nanofibers

Climate change and greenhouse gas emissions have sparked interest in developing efficient CO₂ conversion technology. Photocatalytic CO₂ conversion, using semiconductor materials like Titanium dioxide (TiO₂), has shown promise through solar-powered processes. The efficiency of these photocatalysts depends on understanding charge carrier dynamics. Our study compares the charge carrier kinetics in photocatalytic CO₂ conversion between TiO₂ nanopowder (TiO₂-NP) and TiO₂ nanofibers (TiO₂-NFs). The study uses advanced experimental techniques SEM, XRD, BET, Raman and UV-Vis spectroscopy to analyze the structural and morphological properties of TiO₂ nanopowder and nanofibers, demonstrating their various morphologies. The results show significant differences between the two materials, TiO₂ nanofibers have reduced recombination rates and longer lifetimes due to enhanced charge separation and increased surface-to-volume ratio. TiO₂ nanopowder's increased crystallinity and larger grain size make it harder to segregate charges, leading to shorter lifetimes and higher recombination rates. As result, distinct peaks were seen in the HPLC study of CO₂ conversion over the catalysts for methanol and ethanol with enhanced yield of 182.8 and 216.0 mcg/l respectively for nanofibers. These findings could guide the design and optimization of TiO₂-based photocatalysts for effective CO₂ conversion.