Preparation of Cqds/Pppd by Atmospheric Pressure Microwave Method and its Photocatalytic Performance in Microwave Electrodeless Lamp Catalytic System

CQDs/PpPD (poly(p-phenylenediamine)) were successfully prepared from glucose and p-phenylenediamine using a simple microwave-assisted method at atmospheric pressure. The structure, morphology and properties of CQDs/PpPD were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) and ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS). CQDs/PpPD are a photocatalyst with irregular flakes of PpPD as the main body, evenly distributed carbon quantum dots with a diameter of 2-5 nm on the surface, a strong capacity for absorbing visible light and ultraviolet light, and a low electron hole recombination rate. The experimental results of photocatalytic degradation of rhodamine B (RhB) show that CQDs/PpPD had high photocatalytic activity in the microwave electrodeless lamp (MEDL) catalytic system. In 10 minutes, the degradation rate of RhB solution (50 mL) with a concentration of 50 mg·L −1 reached 91.8% with 0.02 g of CQDs/PpPD catalyst, and the catalyst was recovered by centrifugation and reused. Finally, the main active species in the photocatalytic process were confirmed by adding a capture agent in the photocatalytic experiment. Combined with the characterization results obtained using UV–vis DRS and PL, the mechanism of improving the photocatalytic performance of CQDs/PpPD was preliminarily explored