High-Performance Room-Light-Driven β-AgVO3/mpg-C3N4 Core/Shell Photocatalyst Prepared by Mechanochemical Method

Abstract

A new highly efficient, visible light active, silver vanadate/polymeric carbonitride “core/shell” photocatalyst was prepared mechano-chemically prepared by grinding mixtures of β-silver vanadate and mesoporous graphitic carbonitride. Besides the core/shell photocatalyst, β-silver vanadate/mesoporous polymeric carbonitride composites and supported mpg-C3N4@β-silver vanadates were prepared. The materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen ad- and de-sorption, diffuse reflectance UV-Vis measurement (DRS), infrared spectroscopy, Raman microscopy, and time-resolved photoluminescence spectroscopy. The photocatalytic performance of the materials was investigated in the degradation of organics using pharmaceutical ibuprofen and 4-(isobutyl phenyl) propionic acid sodium salt as model compounds under batch conditions. Reaction intermediates were studied by electrospray ionization and time-of-flight mass spectrometry (ESI-TOF-MS). Additionally, the degree of mineralization was determined by total organic carbon TOC measurements. The core/shell photocatalyst has shown superior photocatalytic activity compared to the other prepared composites or supported photocatalysts as well as the single mpg-C3N4. Scavenger experiments showed that valence band holes and anionic superoxide radicals are the main active species in the photocatalytic process. TOC measurement confirmed the mineralization of the organic compound, which was in line with ESI-TOF-MS experiments. Time-resolved photoluminescence measurements indicated that charges generated in carbonitride migrate via diffusive hopping and exhibit increased mobility in the case of the silver vanadate/polymeric carbonitride composite.