Photoreforming of fermentation byproducts by TiO2 and Pt/TiO2 to enhance hydrogen production: Insight into a real perspective

Abstract

This research was focused on evaluating TiO2 and Pt/TiO2 for hydrogen production through the photoreforming of fermentation byproducts in a solution exposed to UV-LED irradiation. It was also proposed a modification of the generalized kinetic model to predict photocatalytic hydrogen production. Hydrogen production in water matrix with Pt/TiO2 was 27.9 times higher than with bare TiO2 (79.5 μmol H2/gcat). Additionally, tests with Pt/TiO2 and phosphate buffer matrix resulted in a 60% decrease in H2 yield; the presence of inorganic species in the buffer reduced the activity of Pt/TiO2 due to the scavenging of the generated reactive species. Photoreforming tests using real fermentative effluent also demonstrated a notable decrease in activity due to the presence of inorganic ions. Regardless of the solvent matrix, Pt acted as an electron trap, thereby enhancing the photocatalytic activity of TiO2. The metallic Pt on TiO2 also generated plasmonic effects that improved photon absorption (2-fold compared to bare TiO2), increasing the effectiveness of incident radiation. Finally, the kinetic model validates the photoreforming approach with high accuracy.