One-pot Synthesis of a Visible-light Responsive Carbon Nitride/TiO2 Heterointerface Material for Photoelectrocatalytic Applications

Abstract

The rapid integration of green, clean, and renewable technologies in a circular economy requires stable, abundant, and visible-light responsive absorbers. The ideal solar energy harness and conversion process uses a single material that fulfills photon absorption, exciton dissociation, carrier migration, and surface activity requirements. Heterojunctions enable multiple charge pathways, inhibiting recombination while promoting charge transfer across the heterointerface. This study pinpoints the synergy of combining titanium dioxide (TiO2) anatase with carbon nitride (CN) to create a hybrid TiO2(90%)-CN(10%) heterointerface through a one-pot thermal step. The composite outperforms TiO2 and CN references in four individual photo and photoelectrocatalytic reactions. In benzylamine photooxidation, the TiO2(90%)-CN(10%) composite achieved a four-fold increase with 51% conversion at 625 nm (red light). In photocatalytic hydrogen production, Pt/TiO2-CN outperformed references by 1.9-fold and 1.6-fold, yielding 319 and 148 μmol h-1 g-1 at 465 and 410 nm (blue and violet lights). Photoelectrochemical characterization using 410 nm filter performed 23% of the full-spectrum measurement. The composite displayed unprecedented TiO2 photosensitization under visible-light, attributed to improved charge transfer, prolonged lifetimes, and the multiple charge carrier pathways.