Conjugated system in metal-free 1D polyaniline nanotubes/carbon nitride hollow composites with strong adsorption and enhanced visible-light photocatalytic activities

Metal-free 1D polyaniline nanotubes/carbon nitride (PNCN) hollow composites are fabricated by self-assembly chemisorption and solvent evaporation method for the first time. The results show that carbon nitride (g-C 3 N 4 ) is successfully covered onto polyaniline (PANI) nanotubes. Due to similar electronic structures of nitrogen-rich materials of PANI and g-C 3 N 4 , the combination of two π-conjugated system not only benefits the separation of photogenerated charge carriers but also increases the light absorption range of g-C 3 N 4 . The compact contact of the PANI nanotubes and g-C 3 N 4 nanosheets as well as their matched energy level is the determinant factor for interfacial heterojunction. Specially, the hollow 1D “Janus” heterojunction impels photogenerated charge pairs to separate and transfer to opposite directions in a short diffusion path, with the additional benefits of exposure of more active sites and transmission of reactants for catalytic surface reactions. As expected, PNCN composites are photoactive and exhibit enhanced photocatalytic performance under visible-light irradiation over pure g-C 3 N 4 and PANI nanotubes. In addition, PNCN composites possess strong adsorption capacity. This versatile 1D PNCN hollow composites prepared from a cost-effective and green process have potential applications in catalysis, drug delivery system, sensors, and energy storage and conversion.