1D/2D carbon-doped nanowire/ultra-thin nanosheet g-C3N4 isotype heterojunction for effective and durable photocatalytic H2 evolution

Abstract

It is still challenging to design effective g-C3N4 photocatalysts with high separation efficiency of photo-generated charges and strong visible light absorption. Herein, a simple, template-free and “bottom-up” strategy has been developed to prepare 1D/2D g-C3N4 isotype heterojunction composed of carbon-doped nanowires and ultra-thin nanosheets. The ethanediamine (EE) grafted on melamine ensures the growth of 1D g-C3N4 nanowires with high carbon doping, and the ultra-thin g-C3N4 nanosheets were produced through HCl-assisted hydrothermal strategy. The apparent grain boundary between 2D nanosheets and 1D carbon-doped nanowires manifested the formation of the isotype heterojunction. The built-in electric field provide strong driving force for photogenerated carriers separation. Meanwhile, the doping carbon in g-C3N4 nanowires promotes visible light absorption. As a result, the photocatalytic H2 evolution activity of 1D/2D g-C3N4 isotype heterojunction is 8.2 time that of the pristine g-C3N4, and an excellent stability is also obtained. This work provides a promising strategy to construct isotype heterojunction with different morphologies for effective photocatalytic H2 evolution.