Thermal analysis of intermediates formed during preparation of a Pt/WOx/Al2O3 catalyst for 1,3-propanediol synthesis from glycerol
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The platform chemical product 1,3-propanediol can be synthesized via the catalytic process starting from bioglycerol, the commercial by-product of biodiesel production, and the catalyst for this process is under development. In the present work, TG–DTA and TPR-H2 methods were applied to study the effect of preparation conditions on the properties of the most efficient 2%Pt/10%W/Al2O3 catalytic materials that were prepared by H2PtCl6 supporting on W-modified alumina, which was preliminarily synthesized from ammonium paratungstate and the high-surface (200–260 m2 g−1) boehmite. Thermal treatment of the intermediate W-modified boehmite resulted in the γ-Al2O3 support at 550 °C, yet the calcination temperature of 800 °C was required to avoid the W leaching during the next step of H2PtCl6 deposition and in the reaction. The intensive decomposition of supported Pt compounds proceeded up to 550 °C resulting in Pt0 nanoparticles and several Ptn+ species reducible in the range of 0–600 °C. The enhanced hydrogen consumption at 600–840 °C indicated a strong interaction between Pt0 nanoparticles and WOx species. The reducibility of the prepared materials depended on the boehmite origin, on the conditions of polytungstate deposition, and on the calcination temperature of the terminal material. The possible genesis of materials was discussed. The catalytic behavior of the materials in the reaction of glycerol hydrogenation was varied with the reducibility, and the most active materials exhibited the larger hydrogen uptake in the temperature range 60–300 °C.
KeywordsPt–W–Al–O materials TG–DTA TPR-H2 Glycerol hydrogenation 1,3-Propanediol
Electron microscopy characterization was performed in the Department of Structural Studies of Zelinsky Institute of Organic Chemistry, Moscow. The authors thank Prof. I.V. Mishin for the XRD analysis. The work was carried out with a financial support from Russian Science Foundation, Grant No. 17-73-20282.
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