Construction of g-C3N4 nanoparticles modified TiO2 nanotube arrays with Z-scheme heterojunction for enhanced photoelectrochemical properties

Constructing heterojunction structures is an effective way to produce highly efficient photocatalysts with favorable charge transfer paths. In this study, TiO2 nanotube arrays were synthesized using an electrochemical anodization method, and g-C3N4 nanoparticles were grown in situ on TiO2 nanotubes using three thermal polymerization strategies. Compared with pure TiO2, the g-C3N4/TiO2 heterojunctions exhibited different degrees of enhancement in photoelectrochemical performance under stimulated solar light. The TNT-L heterojunction fabricated by urea solution exhibited excellent photoelectrochemical (PEC) activity and followed a Z-scheme mechanism, which is beneficial for carrier separation and maintaining the original redox capacity of each component. The crystallinity, morphology, chemical composition, and optical properties of the photocatalysts were also analyzed using a series of characterization techniques.