Abstract:Bismuth plays important roles in promoting the oxidation of alcohols towards high-valueadded chemicals over a noble metal loading catalyst. Herein, Mg-Al hydrotalcite-supported platinum-bismuth nanoparticles (Pt-Bi/HT) were prepared by the co-impregnation method and used in the selective oxidation of glycerol towards dihydroxyacetone (DHA). The incorporation of Bi species into Pt/HT significantly enhances the conversion of glycerol and the selectivity of DHA. The high selectivity of DHA with 80.6% could be achieved at 25.1% conversion of glycerol. The Bi species of the Pt-Bi/HT catalyst mainly exist in the form of BiOCl and Bi metal, which is different from the previous Pt-Bi based catalyst, confirmed by a combination of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). A plausible mechanism is proposed to elucidate the promoting role of Bi species on the Pt/HT catalyst in the selective oxidation of glycerol towards DHA.

Protic ionic liquids (PILs) are a subgroup of ionic liquids and easily formed by proton transfer from a Brønsted acid to a Brønsted base. Two new crystalline aluminophosphates, [C5H16N2][Al(PO4)(HPO4)] (AlPO-PIL1) and [C5H16N2][Al2(OH)2 (PO4)2] (AlPO-PIL2), are successfully prepared for the first time from a protic ionic liquid, 3-dimethylaminopropylamine acetate. Their structures were determined from single-crystal X-ray diffraction data. It was found that HF in the reaction mixture is crucial in determining the selectivity of the phase. In the absence of HF, AlPO-PIL1 with a one-dimensional chain structure was synthesized by templating the protonated 3-dimethylaminopropylamine cation of the PIL. Upon addition of HF to the initial reaction mixture, AlPO-PIL2 was obtained by templating the protonated N,N'-dimethyl-1,3-propanediamine, which was in situ generated from the protonated 3-dimethylaminopropylamine through migration of methyl groups during the crystallization. AlPO-PIL2 has a novel layered structure with a 3-connected 4·8·8 two-dimensional network which has never been found in the previously reported layered aluminophosphates.

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