Boosting the visible-light photoelectrochemical performance of C3N4 by coupling with TiO2 and carbon nanotubes: An organic/inorganic hybrid photocatalyst nanocomposite for photoelectrochemical water spitting.

Developing photoanode with proficient sunlight harvesting, stability as well as enhancing the electron injection across the interface remains a major challenge in the photoelectrochemical water splitting strategy to generate hydrogen. Herein, we design and fabricate an organic/inorganic TiO 2 /C 3 N 4 /CNT photoanode by a hydrothermal technique which exhibits much enhanced photoelectrochemical properties. The TiO 2 /C 3 N 4 /CNT photoanode exhibits a photocurrent density of 2.94 mA/cm2, which is ~6.4 time higher than pristine graphitic carbon nitride (C 3 N 4) at an applied bias potential of 0.6 V vs. Ag/AgCl. The excellent photoelectrochemical performance benefits from the impactful migration of photo-induced electrons at the TiO 2 /C 3 N 4 interface from C 3 N 4 to TiO 2 and their intimate interface contact with CNT. Kelvin probe force microscopy result shows a smaller interface barrier height (~10 meV) between TiO 2 and C 3 N 4 , suggesting that electrons transport is favored through TiO 2 /C 3 N 4 interfaces in a ternary photoanode. The TiO 2 /C 3 N 4 /CNT photoanode exhibited an onset potential of 0.25 V vs. Ag/AgCl which is much lower compared to pristine C 3 N 4. The electrochemical impedance spectroscopy results also confirmed the enhanced electron injection across the interface in a ternary photoanode. These results demonstrate a promising approach to develop a highly proficient and visible light active photoanode with excellent stability for renewable energy applications. Image 1 • An Organic/Inorganic ternary photoanode was synthesized by the hydrothermal method. • KPFM results shows that electron transport is favored through TiO 2 /C 3 N 4 interfaces. • The ternary photoanode exhibits ~6.4 time higher photocurrent density than C 3 N 4. • The ternary photoanode exhibited excellent photostability. [ABSTRACT FROM AUTHOR]