2D/1D BiOI/g-C3N4 nanotubes heterostructure for photoelectrochemical overall water splitting

To boost the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances, the BiOI/graphitic carbon nitride nanotubes (g-C3N4 nanotubes) heterojunction was synthesized herein through the hydrothermal method. BiOI in-situ grew on the surface of g-C3N4 nanotubes derived from melamine. The rapid recombination between photoexcited electrons and holes of pristine semiconductors was prevented via building the stable heterojunction. The SEM results indicated that the BiOI was wrapped around the surface of g-C3N4 nanotubes, resulting in an optimized electronic transmission pathway. Much lower charge transfer resistance at the p-n heterojunction was demonstrated compared with pristine BiOI according to the EIS results, thus leading to the faster surface reaction rates. Moreover, the composite exhibited both outstanding OER and HER activities under illuminated conditions. This study may shed light upon establishing a bifunctional photoelectrocatalysis for photoelectrochemical water splitting based on stable 2D metal and 1D metal-free nanocomposite.