Three-dimensional reduced graphene oxide aerogel stabilizes molybdenum trioxide with enhanced photocatalytic activity for dye degradation

Abstract

By using three-dimensional reduced graphene oxide (rGO) aerogel as a carrier for molybdenum trioxide (MoO₃), a series of rGO-MoO₃ aerogels were synthesized by a self-assembly process. The results indicated that the as-prepared rGO-MoO₃ aerogel had very low density and good mechanical properties, and would not deform under more than 1000 times its own pressure. The rGO-MoO₃ aerogel showed more than 90% degradation efficiency for MB within 120 min. After six cycles of recycling, the degradation rate of MB only decreased by 1.6%. As supported by the electron paramagnetic resonance (EPR) measurements, the presence of the rGO aerogel enhanced electron conduction, prolonged carrier lifetime and inhibited electron and hole recombination, thus improving the photocatalytic efficiency of composite aerogel. Besides, the hydroxyl radical (OH˙) and radical anion (˙O₂⁻) played an important role in the photodegradation of the dye. The outstanding adsorption and photocatalytic degradation performance of the rGO-MoO₃ aerogel was attributed to its unique physical properties, such as high porosity, simple recycling process, high hydrophobicity, low density and excellent mechanical stability. The findings presented herein indicated that the rGO-MoO₃ aerogel had good application potential, and could serve as a promising photocatalyst for the degradation of dyes in wastewater.