Catalytic conversing heavy concentrations of nitroarenes to aminoarenes over Cu2O/Cu/SrTiO3 three-phase hybrid under flow conditions

The conversion of the heavy concentration of nitroarenes into their corresponding non-toxic aminoarenes is very meaningful for both environment and industrial applications. In this study, a series of Cu2O/SrTiO3 nanocomposites and further Cu2O/Cu/SrTiO3 via Cu+ reducing in situ during the reactive proceeding were fabricated and applied to reduce nitroarenes. The as-prepared composites present high reductive activity and reusable stability for 4-nitrophenol both under the continuous multi-batch ways and flow conditions. The test in an enlarged level revealed 4-nitrophenol (10 L, 0.01 mol L-1) could be quickly conversed to 4-aminophenol over the as prepared sample (300 mg) within 1 h under continuous flow conditions by a self-designed device. The mechanism investigation proposed that Cu-0/Cu+1 pairs serve as a hydrogen and electron transferred shuttle to promote the reductive ability while SrTiO3 as a protective agent packs up tetrakaidecahedron Cu2O to achieve a substantial increase in the stability of the catalyst. The existence of a Cu2O-Cu-SrTiO3 three-phase interface in the hybrid is proved to play the key roles in the greatly enhanced electron transfer ability and the better catalytic activity. The present investigation indicates that the as-prepared samples may be effective and potential materials for the cleaner and sustained conversion of nitroarenes to aminoarenes on a lab level as well as a larger scale. (C) 2019 Elsevier Ltd. All rights reserved.