Facile reduction of para-nitrophenols: catalytic efficiency of silver nanoferns in batch and continuous flow reactors

The catalytic efficiency of silver-nanoferns (Ag-NFs) decorated on carbon microfiber surfaces has been investigated. The Ag-NFs were grown on carbon microfibers employing electrodeposition technique using an electrolytic solution of aqueous silver nitrate and boric acid. The structure of grown Ag-NFs has nanoscaled sub-branches of sizes ≤50 nm that could be controlled by applied voltage and electrodeposition time. Using a specially designed home-made glass reactor, the catalytic efficiency of the Ag-NFs grown over carbon microfibers (cAg-NF) has been measured and tested for a model catalytic reaction of para-nitrophenol reduction mediated by sodium borohydride, both in batch and continuous flow modes of operation. The cAg-NFs have shown excellent catalytic activity with a normalized rate constant κ = 3.42 s^-1 g^-1. The reusability for the cAg-NFs has been observed up to seven cycles of operation without much degradation in the catalytic efficiency. The integrated c-Ag-NF catalyst system and the designed reactors are simple and can be easily incorporated for facile effluent treatment or in other applications where catalytic reduction may be required.