Enhancing photocatalytic hydrogen production: A systematic approach to improving g-C3N4/TiO2 nano-composites
Amen Shahpal, Jennifer Strunk, Rachit Khare, Johannes A. Lercher
Abstract
Aqueous-phase photocatalytic oxidation of isopropanol (IPA) leads to effective H 2 evolution and simultaneous formation of acetone with high selectivity on graphitic carbon nitride ( g -C 3 N 4 )-coated TiO 2 hybrid photocatalysts (denoted as CT). These hybrid photocatalysts were synthesized using a simple, efficient, and scalable ultrasonication strategy. Under optimized conditions, the Pt-decorated hybrid photocatalyst with ∼0.5 wt% Pt loading and ∼2 wt% g -C 3 N 4 loading exhibited high photocatalytic activity for H 2 formation (∼17 µmol H₂ g cat –1 s –1 ). The photoactivity of the hybrid photocatalyst was nearly three-fold that of the parent Pt/TiO 2 photocatalyst (∼5.4 µmol H₂ g cat –1 s –1 ) under similar reaction conditions. The improved photoactivity of the Pt/CT nano-composite material is attributed to (i) increased photon absorption due to modified optical properties and (ii) suppressed electron-hole recombination rates owing to the hybrid band structure . The H 2 generated predominantly results from water splitting, with only minor contributions from IPA dehydrogenation to acetone or its photoreforming to CO 2 . The capture of photo-generated holes by the adsorbed IPA enhances the overall photon efficiency towards water splitting.