Controlling Electronic Properties of Carbon Nitride Nanotubes by Carbon Doping for Photocatalytic H2 Production

Carbon nitride is a promising photocatalyst, but its catalytic performance is inhibited by a low charge-transfer rate and a limited surface area. Herein, a carbon (C)-doped carbon nitride nanotube with abundant π-electrons was developed by using nicotinamide and melamine as precursors through a supramolecular self-assembly method. The experiments and density functional theory (DFT) analysis prove the important function of doped C in catalytic performance. Carbon doping endows carbon nitride with plentiful π-electrons, which effectively promote charge migration and separation. Besides, the nanotubular structure provides unique porous channels for water splitting and an improved light-harvesting ability. Benefiting from the synergic effects of carbon doping and tubular texture, carbon-doped carbon nitride exhibits an excellent H2 evolution rate of 10 089 μmol h–1 g–1 with Pt and triethanolamine (TEOA) as a cocatalyst and a sacrificial agent, respectively, under λ ≥ 400 nm, which is superior to bulk CN (920 μmol h–1 g–1). This significant method offers guidance for the adjustment of the texture and electron density within carbon nitride.