Novel fumed silica/g‐C3N4 composites for highly efficient removal of rhodamine B under visible light emitting diodes light irradiation

Abstract

AbstractGraphitic carbon nitride (g‐C3N4) is a fascinating nonmetallic photocatalyst for the removal of environmental pollutants. The fumed silica/g‐C3N4 (gCN‐FS) composite photocatalysts were successfully fabricated by a combination of solvent volatilization and post‐annealing methods. The introduction of SiO2 not only widens the absorption range of visible light, but also enhances the specific surface area of g‐C3N4. The gCN‐FS‐3 composite has a BET surface area of 129.89 m2/g, which is ~3.3 times as much as that of g‐C3N4 (39.54 m2/g). The gCN‐FS composites have markedly improved rhodamine B (RhB) photodegradation activity in comparison to pure g‐C3N4, bulk g‐C3N4 and P25 under 557 nm yellow‐green light emitting diode light irradiation. The gCN‐FS‐3 has the highest RhB photodegradation rate, which is ~9.67‐, 11.81‐folds as compared to bare g‐C3N4 and bulk g‐C3N4, respectively. The coupling effect between the increase in specific surface areas and the inhibition effect of SiO2 on photogenerated electron/hole pairs recombination is responsible for the enhanced visible light photocatalytic activity of gCN‐FS composite. Superoxide and holes are responsible for the RhB photocatalytic degradation. Furthermore, no apparent loss of photocatalytic activity over five cycles is observed, which indicates that the gCN‐FS composites have considerable stability and reusability in the photodegradation process. The gCN‐FS composites show great promise in visible light driven photocatalysis for environmental applications.