Synthesis of Ag nanoparticles decoration on magnetic carbonized polydopamine nanospheres for effective catalytic reduction of Cr(VI).

More discrete and active Ag nanoparticles (Ag NPs) were fabricated by decorating them on the surface of magnetic nanoparticles encapsulated in carbonized polydopamine nanospheres (M/C-PDA/Ag) via in-situ solid-state decomposition process. The morphology, structure, surface compositions and textural properties of the M/C-PDA and M/C-PDA/Ag catalyst were characterized. The results revealed a dispersion of Ag NPs with average particle size of less than 50 nm on C-PDA nanospheres uniformly embedded with Fe3C NPs of only 3-5 nm in size. With the synergistic effect of Ag NPs, nitrogen doping, and hierarchical mesopores, M/C-PDA/Ag displayed a superior catalytic capability for catalytic reduction of toxic Cr(VI) to less-toxic Cr(III) by formic acid as a reductant. Moreover, M/C-PDA/Ag maintained good physicochemical structure and stable activity even after several cycles of reactions. According to the results, the simple synthetic strategy, good stability, highly catalytic activity, and easy magnetic separation property of M/C-PDA/Ag hybrid make it serve as a promising environmentally friendly catalyst for the elimination of Cr(VI).