Solution combustion synthesis of Ag decorated CeO2 nanocomposite for the reduction of nitroaromatic compounds

The catalytic reduction of various nitroaromatic compounds offers a sustainable method for detoxifying the water and addresses diverse industrial needs. Herein, we report the synthesis and application of Ag-CeO2 nanocomposite (NC) as catalyst for reduction of different nitro compounds. The synthesis was carried out by a simple and scalable solution combustion method. As-synthesised Ag-CeO2 NC was subjected to various characterization techniques such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) to confirm the phase formation, morphology, oxidation states, and specific surface area, respectively. The conditions employed in the synthesis resulted in the formation of crystalline CeO2 decorated with Ag nanoparticles uniformly. The efficiency of Ag-CeO2 NC was evaluated for the reduction of different nitroaromatic compounds by employing sodium borohydride (NaBH4) as the reducing agent. The NC exhibited enhanced catalytic activity when compared to pristine Ag and CeO2 owing to strong synergistic interaction between Ag and CeO2. For the model compound 4-Nitrophenol (4-NP), the rate constant was evaluated to be 1.190 min-1 which is comparable to, and in some cases, even higher than other Ag-CeO2 based catalysts reported in the literature. Further, the catalyst showed excellent stability and recyclability up to ten cycles. Other nitroaromatic compounds such as Nitrobenzene, Nitroanilines, Picric acid etc., could also be reduced efficiently using the Ag-CeO2 NC.