Influence of Boron, Tungsten and Molybdenum Modifiers on Zirconia Based Pt Catalyst for Glycerol Valorization.

Manuel Checa,Jesús Hidalgo-Carrillo,Alberto Marinas,Vicente Montes,Francisco Urbano

doi:10.3390/nano9040509

Manuel Checa, Jesús Hidalgo-Carrillo + Show 3 more

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https://doi.org/10.3390/nano9040509

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Journal: Nanomaterials	Publication Date: Apr 2, 2019
Citations: 14	License type: CC BY 4.0

Affiliation: University of Extremadura, University of Córdoba

Abstract

The influence of boron, tungsten and molybdenum modifiers on zirconia-based Pt catalyst was studied for glycerol valorization. Zirconia modified supports were prepared by impregnation of ZrO2 with either boric, silicontungstic or phosphomolybdic acids to obtain supports with enhanced Brönsted acidic properties. The modified supports were subsequently impregnated with chloroplatinic acid to obtain Pt-based catalysts. Pt incorporation resulted in the increase in Lewis acidity of the solids, being more significant for the Pt//W/ZrO2 catalyst. Reduced Pt catalysts were tested for the liquid-phase glycerol hydrogenolysis, observing a synergistic effect between catalyst acid sites and metal function that proved to be crucial in glycerol hydrogenolysis. The Pt//W/ZrO2 catalyst was the most active catalyst in this reaction, being the only leading to 1,3-PDO (45% sel., 160 °C) while Pt//Mo/ZrO2 is the best option for 1,2-PDO (49% sel., 180 °C). Reusability studies carried out for Pt//W/ZrO2 showed that catalytic activity dropped after the first use, remaining constant for the second and subsequent ones. Selectivity to reaction products also changes during reuses. Therefore, the selectivity to 1,2 PDO increases in the first reuse in detriment to the selectivity to n-propanol whereas the selectivity to 1,3-PDO remains constant along the uses. This behavior could be associated to the lixiviation of W species and/or catalyst fouling during reaction runs.

Highlights

Nowadays, society demands to industries the development of new environmentally friendly processes and chemicals [1]
Three portions were impregnated with the acid modifiers, whereas the fourth unmodified zirconia was used as the reference bare support
inductively coupled plasma with mass spectrometry detection (ICP-MS) shows that Pt incorporation is close to the nominal value, with 4.6 wt.% Pt loading for all catalysts, except for Pt/ZrO2 with 4.8 wt.%

Summary

Introduction

Society demands to industries the development of new environmentally friendly processes and chemicals [1]. The substitution of petrol-based fuel by renewable raw materials as vegetable oils can considerably reduce their environmental impact [3] In this line, many countries have built facilities in order to increase their biodiesel production as, for example, European countries whose production represents up to 30% of the global production [4]. Many countries have built facilities in order to increase their biodiesel production as, for example, European countries whose production represents up to 30% of the global production [4] Such increment directly affects glycerol markets since biodiesel industries generate 1 kg of bioglycerol (as by-product) per 10 kg of biofuel [4,5,6]. The low cost of glycerol, together with the high functionality of this molecule, make it an ideal starting material for several chemical routes [11]

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