Atomic Layer Deposition of a Pt-Skin Catalyst for Base-Free Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid

A Pt-Ni/AC bimetallic catalyst was prepared by atomic layer deposition of Pt nanoparticles on the surface of Ni/AC for base-free oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (2,5-FDCA). A comparison of the Pt-Ni bimetallic catalyst with Ni and the Pt monometallic catalyst was demonstrated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and temperature-programmed desorption of CO (CO-TPD). Compared with the Ni/AC and Pt/AC (1.6 wt % Pt) catalysts, the bimetallic Pt-Ni/AC catalyst had a higher activity for the oxidation of 5-HMF to 2,5-FDCA, with only a 0.4 wt % Pt loading. A 97.5% yield of 2,5-FDCA with 100% 5-HMF conversion was obtained after 15 h at 100 degrees C. A mass-based activity value of 35.8 h(-1) was obtained over the Pt-Ni/AC-15ALD catalyst. The combination of Pt with Ni increased the ability of Pt for C=O adsorption and oxidation, thus increasing the activity of the Pt catalyst. Finally, the catalyst showed good reusability for at least four times without any reduction in the catalytic activity.