Ultrafast Charge Injection in Silver-Modified Graphitic Carbon Nitride

Abstract

Graphitic carbon nitride (gCN) is a promising organic platform for driving light-activated charge-transfer reactions in a number of valuable photocatalytic cycles. A primary limitation of gCN as a photocatalyst is its short excited-state lifetime, which is mediated by a high density of trap and defect sites that result in rapid excited-state decay and low photocatalytic efficiency. To enhance the catalytic activity, gCN is often functionalized with a metal co-catalyst; however, the mechanism by which metal co-catalysts enhance the reactivity has not been clearly established. In this work, the excited-state dynamics of gCN and silver-modified gCN are compared using ultrafast transient absorption and time-resolved photoluminescence spectroscopies. In silver-modified gCN, an ultrafast spectral shift in the silver plasmon resonance provides direct spectral evidence of electron transfer from gCN to the silver nanoparticles. The electron-transfer rate is competitive with other non-radiative relaxation pathways, with electron-transfer yields approaching 50%, thus providing an effective strategy for mitigating losses associated with defects and trap sites.

High-Efficiency Ag-Modified ZnO/g-C3N4 Photocatalyst with 1D-0D-2D Morphology for Methylene Blue Degradation

“…The synthesized 1D-0D-2D Ag-ZnO/g-C 3 N 4 photocatalyst enabled the high-speed transfer of electrons between the components. The Ag nanowires act as natural conductors that capture electrons and accelerate electron transfer [34]. The ZnO nanoparticles and fluffy g-C 3 N 4 nanosheets provided a large number of reactive active sites.…”