The mechanism insight for improved photocatalysis and interfacial charges transfer of surface-dispersed Ag0 modified layered graphite-phase carbon nitride nanosheets

Abstract

A series of surface-dispersed Ag0 modified lamellar-graphite-phase carbon nitride nanosheets (Ag/LGCNs) are synthesized by a straightforward method to construct the noble metal/semiconductor heterojunction. The localized surface plasmon resonance (LSPR) effect results in an optimum degradation rate (Kapp) for rhodamine B ∼ 5.53 × 10−2∙min−1 (9 times higher than that of pure LGCNs), and the sample exhibited outstanding stability. The experiments with sacrificial reagents showed that the h+ and ∙O2– are primary active photocatalytic species in the present samples. The optical and photo-electro-chemical studies of the samples, confirm enhanced photo-responsiveness and photogenerated carriers' separation and transport with an appropriate amount of Ag0. The corresponding mechanism is formulated using photocurrent analysis, impedance analysis, finite-difference time-domain (FDTD) simulation and density functional theory (DFT). FDTD simulation evidenced an intense electromagnetic field at the Ag/LGCN’s interface under visible radiation attributable to the LSPR effect of Ag0 nanoparticles and an increased field intensity with the size of Ag0 nanoparticles. The DFT computations show that the difference in Fermi energy level and the work function contributes to an interfacial built-in electric field between Ag0 nanoparticles and LGCNs. Furthermore, the mechanism for reduced band gap and improved photocatalytic performance for Ag/LGCNs is explained by the energy band studies.