One-step preparation of reduced graphene oxide/Prussian blue/polypyrrole aerogel and their enhanced photo-Fenton performance

In this manuscript, hierarchical porous reduced graphene oxide/Prussian blue/polypyrrole (rGO/PB/PPy) aerogel with a surface area of 70 m²/g was prepared and used as a photo-Fenton catalyst. In aerogel, rGO nanosheet acted as skeleton, PPy as cross-linker and PB nanoparticle as active site. The influence of experimental parameters, including H₂O₂ dosage, rhodamine B (RhB) concentration, catalyst amount, and pH value, on degradation efficiency was investigated. The optimal condition was: 10 mg of catalyst, 10 mg/L of RhB, 100 µL of H₂O₂, and 6.18 of pH value. Under this condition, 95.2% of RhB was degraded within 30 min and the rate constant was 7.66 × 10⁻² min⁻¹. Activation energy, enthalpy change, entropy change, and Gibbs free energy change (298 K) were calculated to be 35 kJ/mol, 35 kJ/mol, 96.5 J/mol K, and 6.4 kJ/mol, respectively. In cyclic experiments, 91.5% of degradation efficiency was remained after the 4^th cycle. Besides RhB, other dyes and antibiotics also could be degraded within 75 min. The inhibitory effect of anions was investigated, and H₂PO₄ ⁻ had the most significant influence.