Bimetallic Au–Pd/MgO as efficient catalysts for aerobic oxidation of benzyl alcohol: A green bio-reducing preparation method

The oxidation of benzyl alcohol, with molecular oxygen at atmospheric pressure in an aqueous medium, is investigated using Au–Pd/MgO bimetallic catalysts to examine the effect of catalyst parameters (viz. preparation method, Au/Pd molar ratio, and calcinations temperature) and reaction conditions (viz. reaction temperature and oxygen flow rate) on conversion and selectivity. The bimetallic catalysts were prepared via two novel reduction methods with bio-reducing agents and were characterized by transmission electron microscopy, X-ray diffraction, diffuse reflectance UV–vis spectroscopy, and thermogravimetric analysis to understand synergistic interactions between Au and Pd. Under optimal conditions, the Au–Pd bimetallic catalysts, with a 1:1 molar ratio and 9.7 ± 1.3 nm particle size, exhibited remarkably enhanced catalytic activity (>52%) and selectivity (∼100%) compared with their monometallic counterparts. Moreover, the activity of the catalysts was maintained after six recycles without agglomeration.

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► Au–Pd bimetallic catalysts were prepared by green bio-reducing methods.
► Catalysts were characterized to understand the Au–Pd synergistic interactions.
► Bimetallic catalysts showed superior performance for benzyl alcohol oxidation.
► The effects of conditions on the catalytic performance were investigated.