Elucidation of a Core-Shell Structure in Phenyl-Grafted Carbon Nitride/TiO2 Nanohybrids for Visible-Light-Mediated H2 Production with Simultaneous Rhodamine B Degradation

Abstract

Dual-functional photocatalysts help to maximize resource utilization in water remediation, but often they are visible-light-inactive, toxic, and cost-intensive. Herein, a type-II heterojunction visible-light-active photocatalyst is reported for tandem degradation of Rhodamine B and generation of H2. A Rhodamine B degradation rate of 2.3 × 10-2 min-1 and H2 production activity of 5789 μmol h-1 g-1 are shown. The hybrid shows a gradient core-shell morphology with a visible - light-absorbing phenyl-modified carbon nitride (PhCN) core and a porous PhCN/TiO2 outer shell, resulting in an enhanced interaction between the catalyst and the surroundings. The nanoscale crystallization of TiO2 on PhCN's surface, shifts the triazine network structure, while autoclave treatments further increase the band gap and suppress charge carrier recombination. The influence of nanoscale morphological changes on photocatalytic activity was examined by varying the component ratios and thermal treatments, highlighting the strong correlation between the nanoscale architecture and the enhanced catalytic activity. This work provides a detailed guide to the exploration of environmentally friendly dual-functional photocatalysts.