Construction of carbon nanotube-g-C3N4 nanocomposite photoanode for the enhanced photoelectrochemical activity in water splitting

A nanocomposite of g-C3N4 with carbon nanotubes (CN-CNT) was synthesized by polycondensation and deposited on FTO substrate via electrophoretic technique. The crystal structure, surface morphology, chemical composition and optical absorption of pure g-C3N4 and the synthesized CN-CNT nanocomposite film were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. SEM analysis showed the interconnected structure for CN-CNT nanocomposite film due to the CNTs. From UV-Vis spectroscopy, the CN-CNT nanocomposite electrode implied the band gap of 2.35 eV, significant reduction relative to pure g-C3N4 electrode (2.60 eV). Photocurrent at 0.3 V vs Ag/AgCl for the CN-CNT photoanode was 6 fold higher than that of the g-C3N4 photoanode, originating from the enhanced charge separation and transfer between g-C3N4 and CNTs and light absorption. Photoelectrochemical measurements indicate that the CNTs in the CN-CNT nanocomposite photoanode was beneficial for improving light absorption edge, charge separation and transport. (c) 2020 Elsevier B.V. All rights reserved.