A self-assembly strategy to synthesize carbon doped carbon nitride microtubes with a large π-electron conjugated system for efficient H2 evolution

The combination of element doping into carbon nitride and developing a novel structure is charming in realizing outstanding photocatalytic performance. Herein, carbon-doped carbon nitride microtubes with a large π-electron conjugated system were developed via a facile self-assembly strategy. Glucosamine hydrochloride, a substance with abundant hydroxyl and amino, and melamine were applied as precursors based on the self-assembly behavior via hydrogen bonds. The glucosamine hydrochloride content and the formation of hydrogen bond have impacts on self-assembly behavior to fabricate a rod-shaped precursor. Afterwards, carbon-doped carbon nitride microtubes are synthesized after calcination. The effective π delocalization induced by C doping and unique tubular morphology facilitate charge carrier transfer, offer plentiful active sites as well as the improved visible light capture efficiency. Therefore, carbon-doped carbon nitride microtubes display an outstanding H2 generation rate of 3888.9 μmol h−1 g−1 under λ > 400 nm, far beyond that of pure carbon nitride (886.3 μmol h−1 g−1). Experimental and density functional theory calculation demonstrate that carbon doping endows adjustable band structure, narrow band gap, enhanced π electron density and fast charge transfer rate, finally boosts photocatalytic activity. Our work gives a facial way for fabricating C doped carbon nitride with optimized structure and catalytic performance, which offers an efficient method to develop heteroatoms-doped carbon nitride.