In order to investigate the effect of support particle size on the catalytic performance of Pd/γ-Al2O3 for the benzyl alcohol oxidation under solvent-free,two different kinds of Pd/γ-Al2O3 catalysts with micrometer-sizedγ-Al2O3-V and nanometer-sized γ-Al2O3-N as support and Pd as the active component were prepared by using the impregnation method,respectively.The experimental results indicate that the particle size of γ-Al2O3 has a significant influence on the catalytic activity of the Pd/γ-Al2O3 catalysts.Compared to the Pd/γ-Al2O3-V(Ea=127.4 kJ/mol),the Pd/γ-Al2O3-N with smaller support particle sizes exhibits a significantly lower reaction activation energy(Ea=82.1 kJ/mol),thereby possessing a higher catalytic activity.By analyzing the structural characterization results of the catalysts by using X-ray diffraction(XRD),N2 physical adsorption(N2-BET),inductively coupled plasma atomic emission spectrometry(ICP-AES),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS),it could be found that the key factors to obtain the excellent catalytic performance of the Pd/γ-Al2O3-N are attributed to the smaller Pd nanoparticle size,the larger pore volume and pore size,and the more abundant Pd0 species on the catalyst surface.
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