Co75Pt25 alloy nanoparticles: A class of catalyst for the catalytic reduction of 4-nitrophenol with enhanced activity and recycling

We report a facile one-step, co-chemical reduction controlled synthesis of Co x Pt 100-x (x = 25, 35, 50, 65, 75) alloy nanoparticles (NPs). Alloy NPs with Co to Pt atomic ratios of 25/75, 50/50 and 75/25 were found to exhibit a pure phase and superpara-magnetism with a small NP size distribution. The saturation magnetization for Co 75 Pt 25 NPs (55.17 emu/g) was highest than that for Co 25 Pt 75 NPs (47.58 emu/g) and Co 50 Pt 50 NPs (32.38 emu/g), confirmed the best magnetic response of Co 75 Pt 25 NPs. Furthermore, the average crystallite sizes for Co x Pt 100- x (x = 25, 50, 75) alloy NPs is 5.72 nm, 5.43 nm and 5.6 nm, respectively. The observation of an obviously reduced catalytic reduction time and increased rate constant confirmed that the Co x Pt 100- x (x = 25, 50, 75) alloy NPs exhibit intensive performance for the catalytic reduction of 4-nitrophenol (4-NP). Moreover, compared with Co 25 Pt 75 and Co 50 Pt 50 alloy NPs, the Co 75 Pt 25 alloy NPs exhibit short reaction times for catalytic reduction due to their stability in aqueous solution and short induction time. The recycling ability of the alloy catalysts was certified with high yields in four reaction cycles.