Synthesis of high-efficient g-C3N4/polydopamine/CdS nanophotocatalyst based on bioinspired adhesion and chelation

By utilizing the bioinspired adhesion and metal chelation of polydopamine (PDA), a kind of ternary nanocomposites that consist of the graphitic carbon nitride nanosheet (CNNS), PDA layer and cadmium sulfide (CdS) nanocrystals were synthesized. In the resultant CNNS/PDA/CdS nanocomposites, CdS nanocrystals about 5−10 nm in diameter are scattered on the CNNS surface in the presence of the PDA layer. Due to the energy band matching, CNNS constructs a type II heterostructure with CdS nanoparticles via the mediation of the electroconductive PDA layer, thus enhancing the photocatalytic activity. Compared with pristine CdS and CNNS, the CNNS/PDA/CdS nanocomposite conspicuously shows superior photocatalytic performance under visible light above 420 nm, which can degrade 97 % Rhodamine B (RhB) molecules within 80 min. The introduction of a PDA layer between CNNS and CdS not only promotes the photon energy absorption but also facilitates the separation of photoinduced electron-hole pairs.