Preparation and enhanced visible light photoelectrochemical activity of g-C3N4/ZnO nanotube arrays

Graphite-like carbon nitride particles were deposited onto ZnO nanotube arrays by thermal polycondenzation and the photoelectrochemical energy conversion property of the g-C3N4/ZnO photocathode was investigated. The photocurrent generated by the g-C3N4/ZnO composite photocathode is nearly five times as that of g-C3N4 and ten times as that of ZnO under visible light irradiation at applied potential of +0.40 V vs. Ag/AgCl electrode. The incident photon to electron conversion efficiency is also greatly enhanced after the modification of g-C3N4 nanoparticles onto the ZnO nanotube arrays. In addition, the g-C3N4/ZnO electrode exhibits excellent long-term stability. The matching conduction bands and valence bands of g-C3N4 and ZnO greatly enhanced the separation and transfer of the photogenerated electrons and holes in the composite, thus the photoelectrochemical performance of the g-C3N4/ZnO electrode is improved.