Perylene tetracarboxylic bisimide decorated g-C3N4 with enhanced photocatalytic activity

Abstract

A water-soluble perylene bisimide derivative, N, N'-di(2-succinic acid)-perylene-3, 4, 9, 10-tetracarboxylic bisimide (PASP) was synthesized by using 3, 4, 9, 10-perylenetetracarboxylic dianhydride and L-aspartic acid as starting materials. The PASP were grafted onto graphitic carbon nitride (g-C3N4) via hydrothermal method to prepare PASP modified g-C3N4 hybrid photocatalyst (g-C3N4-PASP). The composition, structure, morphology and optical properties of the prepared g-C3N4-PASP samples were typically characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM), UV-Vis diffuse reflectance spectroscopy(UV-Vis DRS), and solid-state fluorescence spectroscopy. In addition, the photocatalytic activities of the prepared g-C3N4-PASP photocatalysts were evaluated by decomposition of methylene blue(MB) pollutant in water solution under visible light. The results reveal that PASP can be facilely linked to the g-C3N4 covalently via amide bond by hydrothermal treatment; compared to pristine g-C3N4, the g-C3N4-PASP possesses obviously higher specific surface area, dramatic red shifted absorption edge of 614 nm, and more efficient charge separation. Therefore, the visible light photo-catalytic degradation of MB pollution in water over the g-C3N4-PASP is notably improved. The g-C3N4-PASP could degrade 99.4% of MB dyes in 60 min under visible light irradiations (λ >420 nm), with a pseudo-first-order rate constant 2 times higher than that of pristine g-C3N4.

Keywords

• graphitic carbon nitride(g-c3n4)
• perylene tetracarboxylic bisimide
• chemical modification
• photocatalysis