Pyrolytic synthesis of organosilane-functionalized carbon nanoparticles for enhanced photocatalytic degradation of methylene blue under visible light irradiation.

Using carbon-based nanomaterials as effective photocatalyst is an ideal alternative for environmental remediation. Herein, (3-aminopropyl) triethoxysilane (APTES) functionalized carbon nanoparticles (SiCNPs) were prepared through a facile pyrolysis method using sodium citrate and urea as precursors. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and photo-electrochemical measure. The obtained SiCNPs-2.0 showed better visible-light response and more effective photocatalytic activity for degradation of methylene blue (MB) as comparing to pure carbon nanoparticles (CNPs). Under visible light irradiation, 98.8% of the MB was decomposed within 75 min using SiCNPs-2.0 as photocatalyst. The high photocatalytic activities of SiCNPs-2.0 could be attributed to the enhanced light absorption in the visible region, and improved photo-generated electron-hole separation efficiency. Furthermore, the possible photocatalytic mechanism for removal of MB over SiCNPs-2.0 was proposed according to active species trapping experiments. The recycling experiments showed that SiCNPs-2.0 had good stability during photocatalysis. This work provides an easier new method to synthesize carbon-based nanomaterials and to catalytically degrade organic pollutants in water under visible light irradiation.