Graphitic carbon nitride (g-C3N4) coated titanium oxide nanotube arrays with enhanced photo-electrochemical performance

Abstract

Herein, we report the successful formation of graphitic carbon nitride coated titanium oxide nanotube array thin films (g-C₃N₄/TiO₂) via the facile thermal treatment of anodized Ti sheets over melamine. The proportion of C₃N₄ and TiO₂ in the composite can be adjusted by changing the initial addition mass of melamine. The as-prepared samples are characterized by several techniques in order to understand the morphological, structural, compositional and optical properties. UV-vis absorption studies exhibit a remarkable red shift for the g-C₃N₄/TiO₂ thin films as compared to the pristine TiO₂ nanotubes. Importantly, the prepared composites exhibit an enhanced photocurrent and photo-potential under both UV-vis and visible light irradiation. Moreover, the observed maximum photo-conversion efficiency of the prepared composites is 1.59 times higher than that of the pristine TiO₂ nanotubes. The optical and electrochemical impedance spectra analysis reveals that the better photo-electrochemical performance of the g-C₃N₄/TiO₂ nanotubes is mainly due to the wider light absorption and reduced impedance compared to the bare TiO₂ nanotube electrode. The presented work demonstrates a facile and simple method to fabricate g-C₃N₄/TiO₂ nanotubes and clearly revealed that the introduction of g-C₃N₄ is a new and innovative approach to improve the photocurrent and photo-potential efficiencies of TiO₂.