Catalytic performance of graphene-bimetallic composite for heterogeneous oxidation of acid orange 7 from aqueous...

In this study, reduced graphene oxide (rGO) embedded with bimetallic nanoparticles of cobalt-manganese oxide (CoMn₂O₄) was fabricated by hydrothermal treatment. The obtained product was characterized and applied for the heterogeneous activation of peroxymonosulfate (PMS) to degrade acid orange 7 (AO7). The characterization results revealed that 10-20 nm nanosized CoMn₂O₄ was homogenously decorated on the surface of rGO. The effect of different CoMn₂O₄ loadings showed that catalyst with a CoMn₂O₄ contents higher than 20% performs stronger capability for catalytic degradation of AO7 compared to pure CoMn₂O₄. In a system containing 4 mM PMS and 0.05 g/L 50% CoMn₂O₄/rGO, 100% conversion of AO7 (70 mg/L) and 43% mineralization could be achieved within 12 and 60 min, respectively. Recycling experiment along with XRD data demonstrates good stability of the catalyst for five successive runs. Inhibition confirmation results suggest that surface-bound SO₄^•- and HO^• radicals both played a key role in degradation of AO7. Therefore, this material demonstrates a very efficient catalytic performance for the degradation of organic dyes.