Synthesis of ascorbic acid enhanced TiO2 photocatalyst: its characterization and catalytic activity in CO2 photoreduction

Abstract

To date, the development of solar environmental remediation has shifted more emphasis on the green and simple synthesis of catalyst for CO₂ photocatalysis process. Herein, TiO₂ photocatalyst was successfully synthesized via hydrothermal method. The effects of the different molar ratio of ascorbic acid C₆H₈O₆, (AA) added during the preparation of TiO₂ nanoparticles were comprehensively studied. The characterization of TiO₂ nanocrystals was performed via XRD, XPS, DRUV-vis, and FTIR. The results show the AA loading into TiO₂ nanoparticles significantly intensified the XRD spectra of anatase structure. In fact, this feature had signified a reactivity of the photocatalyst in the visible region. In an instance, BET surface area was also enhanced with the highest recorded value of 135.14 m²/g for 0.8AA. Meanwhile, the CO₂ photoreduction over synthesized TiO₂ had produced the highest amount of HCOOH at 39.3 μmol/g  _cat for 0.8AA within 6 hours of reaction time. Furthermore, the DRUV-vis analysis had illustrated better light absorption ability of 0.8AA. This profound finding is attributed to the correlation between large surface area, pure anatase phase, and high adsorbed water molecules. Therefore, this study had significantly demonstrated the potential of modified TiO₂ with AA in CO₂ photocatalysis area while simultaneously presents a green and simple method for TiO₂ synthesis.