Hollow tubular carbon doping graphitic carbon nitride with adjustable structure for highly enhanced photocatalytic hydrogen production

Carbon nitride, considered to be a promising photocatalyst, still has much room to increase the catalytic performance owing to the slow charge transfer and limited light harvesting ability. Herein, carbon doping carbon nitride with hollow tubular structure was successfully developed by using melamine and sodium alginate as precursors via a simple hydrothermal calcination method. The effects of carbon content on the structure and photocatalytic activities of as-obtained carbon nitride were researched in detail. The hollow tubular structure can assist the enhancement of specific surface area, increase of visible light harvesting ability and enhancement of electron transport ability. Simultaneously, carbon doping can adjust the photoelectric performance and band structure of carbon nitride due to the generation of delocalized big π bonds to enhance the photocatalytic activities. The catalytic performance of as-obtained carbon nitride is estimated by hydrogen evolution reaction. And carbon doping carbon nitride with hollow tubular structure accounts for 3 times and 2 times promotion than pristine CN in hydrogen evolution rate under λ > 420 nm and λ > 400 nm, respectively. Especially, the sample CN-40 shows a highly enhanced hydrogen generation efficiency of 1210.3 μmol h-1 g-1, which should be inseparable from the function of carbon doping and hollow tubular structure.