Insights into the Nature of the Active Sites of Pt-WOx/Al2O3 Catalysts for Glycerol Hydrogenolysis into 1,3-Propanediol

Abstract

The chemo-selective hydrogenolysis of secondary hydroxyls is an important reaction for the production of biomass-derived α,ω-diols. This is the case for 1,3-propanediol production from glycerol. Supported Pt-WOx materials are effective catalysts for this transformation, and their activity is often related to the tungsten surface density and Brönsted acidity, although there are discrepancies in this regard. In this work, a series of Pt-WOx/γ-Al2O3 catalysts were prepared by modifying the pH of the solutions used in the active metal impregnation step. The activity–structure relationships, together with the results from the addition of in situ titrants, i.e., 2,6-di-tert-butyl-pyridine or pyridine, helped in elucidating the nature of the bifunctional active sites for the selective production of 1,3-propanediol.

Selective Hydrogenolysis of Biodiesel Waste Bioglycerol Over Titanium Phosphate (TiP) Catalysts: The Effect of Pt & WO3 Loadings

“…Both Bronsted (BAS) and Lewis acidity (LAS) play an important role; however, BAS is more favorable for selective formation of 1,3-PDO [23]. A similar phenomenon was observed to optimise the WO 3 loading by Jarauta-Córdoba et al, 2021 [29]. The structure-acidity correlation was determined and both LAS and BAS are relevant in the selective production of 1,3-PDO.…”

“…The structure-acidity correlation was determined and both LAS and BAS are relevant in the selective production of 1,3-PDO. Moreover, the BAS enhanced with WO 3 loadings and influenced the acidity towards secondary C-O bond dissociation and hydrogenation but optimization of WO 3 is vital in obtaining favorable acid sites [29]. Overall, the 10 wt.% WO 3 doped catalyst displayed the highest activity in terms of glycerol conversion and selectivity toward the 1,3-PDO compared to all other tested catalysts (Table 3).…”

Transition Metal Catalysts for the Glycerol Reduction: Recent Advances

“…[239] The catalyst was proposed as bifunctional active site, formed by closely interacting Pt species, that activated the hydrogen, and W δ + -O-Al sites, necessary for the adsorption and activation of GL. [240] Good results in the production of 1,3-PD were obtained even in the presence of Pt-WO x /α-Al 2 O 3 calcinated at high temperature. [241] Its preparation method allowed to disperse Pt as single atom on solid surface, with more Pt and WO x interactions.…”

Hydrogenolysis of glycerol over TiO2-supported Pt-WOx catalysts: Effects of the TiO2 crystal phase and WOx loading

“…Efficient conversion of glycerol to 1,3-PDO through selective hydrogenolysis is attraction but challenging. Among the numerous catalysts studied so far, Ir-Re (Yoshinao Nakagawa et al, 2010) (Yasushi Amada et al, 2011) (Deng et al, 2015) (Liu et al, 2019) and Pt-W (Shi et al, 2018) (Jarauta-Córdoba et al, 2021) (Zhu et al, 2015) (Liu et al, 2020) bifunctional catalysts have been reported to exhibit the most promising performance. In particular, Pt-W-based catalysts are more durable and costcompetitive than Ir-Re-based catalysts.…”

“…In most modification studies, it is quite common to change the support to obtain highly active catalysts. Common supports such as ZrO 2 ( Zhou et al, 2016 ), Al 2 O 3 ( Jarauta-Córdoba et al, 2021 ), SiO 2 ( Zhou et al, 2020 ), TiO 2 ( Zhang et al, 2013 ), etc., have been used to conduct the experiments. These supports can improve the activity of the Pt-W catalyst to a certain extent.…”