Graphite carbon nitride coupled S-doped hydrogenated TiO2 nanotube arrays with improved photoelectrochemical performance

Abstract

With the goal of improving the photoelectrochemical performances of titanium dioxide nanotube arrays (TiO2 NTAs), graphitic carbon nitride (g-C3N4)/S-doped hydrogenated TiO2 NTAs (g-C3N4/H-S-TiO2 NTAs) nanocomposite were fabricated by a feasible method. Photoelectrochemical tests showed that the photoelectric conversion efficiency of g-C3N4/H-S-TiO2 NTAs4 was up to 1.47%, which is about 5.44 times than that of TiO2 NTAs. The g-C3N4/H-S-TiO2 NTAs4 exhibited higher transient photocurrent density (1.64 mA/cm2) with good stability than TiO2 NTAs (0.29 mA/cm2). Furthermore, g-C3N4/H-S-TiO2 NTAs4 had a more negative open circuit potential and optimal photoelectric stability than other photoelectrodes. The possible photoelectric mechanism of g-C3N4/H-S-TiO2 NTAs was proposed. Photoelectrochemical characterizations demonstrated that hydrogenation, S-doping and the introduction of g-C3N4 have synergistic effects on the improvement of the photoelectrochemical performances of TiO2 NTAs.