Facile Synthesis of Gold Nanoparticles Decorated Core-Shell Fe₃O₄@Carbon: Control of Surface Charge and Comparison in Catalytic Reduction for Methyl Orange.

We report a facile synthesis of Au nanoparticles (Au NPs) decorated Fe₃O₄@carbon (Fe₃O₄@C) core-shell nanoparticles (denoted as Fe₃O₄@C@Au) with easy inverting the surface charge of the composites through the hexadecyl trimethyl ammonium bromide (CTAB) treatment (denoted as Fe₃O₄@C@Au-CTAB). Nanoparticles of both kinds have been studied as catalysts for an anionic methyl orange (MO) reduction. Fe₃O₄@C@Au-CTAB positively charged exhibits a faster catalytic ability toward anionic MO than negatively charged Fe₃O₄@C@Au, indicating an effect of the electrostatic interaction on catalytic reduction. The facile and green preparation, high catalytic capability, selective surface property and recyclability make Fe₃O₄@C@Au-CTAB an appropriate platform for nanocatalysis in wastewater treatment.