Porosity Tuning of MoS2/Graphene Aerogel via the Boudouard Reaction for Enhanced Degradation of Tetracycline under Visible-Light

Abstract

Composite aerogel photocatalysts (CAPs) offer enhanced stability, easy recovery, and high photocatalytic performance. Optimizing the porosity, morphology, and interconnectivity of the pores in CAPs is essential for effective photocatalysis. In this study, a molybdenum disulfide/graphene CAP was synthesized and modified through physical activation to improve its photocatalytic activity for tetracycline (TC) degradation under visible-light irradiation. Activation with carbon dioxide (CO₂) significantly enhanced photocatalytic performance by increasing specific surface area, pore volume, and mesopore size, thereby improving light absorption and charge separation. This enhancement resulted from the Boudouard reaction, which created pores or defects in the graphene lattice. However, excessive pore formation could compromise the structural integrity of the graphene sheets. The CAP activated at 750 °C degraded 95% of TC in 90 min under visible light, outperforming both unactivated and chemically activated CAPs. These results demonstrate that CO₂-mediated physical activation is a promising approach to improving CAP performance for wastewater treatment.