Capping Agent Effect on Pd-Supported Nanoparticles in the Hydrogenation of Furfural

Shahram Alijani,Claudio Evangelisti,Alberto Villa,Francesca Tessore,Sofia Capelli,Khaled M H Mohammed,Stefano Cattaneo,Marco Schiavoni,Peter P Wells

doi:10.3390/catal10010011

Abstract

The catalytic performance of a series of 1 wt % Pd/C catalysts prepared by the sol-immobilization method has been studied in the liquid-phase hydrogenation of furfural. The temperature range studied was 25–75 °C, keeping the H2 pressure constant at 5 bar. The effect of the catalyst preparation using different capping agents containing oxygen or nitrogen groups was assessed. Polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and poly (diallyldimethylammonium chloride) (PDDA) were chosen. The catalysts were characterized by ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The characterization data suggest that the different capping agents affected the initial activity of the catalysts by adjusting the available Pd surface sites, without producing a significant change in the Pd particle size. The different activity of the three catalysts followed the trend: PdPVA/C > PdPDDA/C > PdPVP/C. In terms of selectivity to furfuryl alcohol, the opposite trend has been observed: PdPVP/C > PdPDDA/C > PdPVA/C. The different reactivity has been ascribed to the different shielding effect of the three ligands used; they influence the adsorption of the reactant on Pd active sites.

Highlights

IntroductionDiminishing fossil fuel resources, a growing energy demand, and the increased environmental concerns caused by CO2 emissions have led to the search for new sustainable energy resources [1,2]
Diminishing fossil fuel resources, a growing energy demand, and the increased environmental concerns caused by CO2 emissions have led to the search for new sustainable energy resources [1,2].In this regard, waste lignocellulosic biomass, which mainly contains cellulose, hemicellulose, and lignin, is considered a promising sustainable resource
The capping agent–H2 O sols are transparent in the visible range; Polyvinyl alcohol (PVA) has a band at 280 nm, which can be attributed to the π → π* transition of the carbonyl groups (C=O) associated with ethylene unsaturation [31]

Summary

Introduction

Diminishing fossil fuel resources, a growing energy demand, and the increased environmental concerns caused by CO2 emissions have led to the search for new sustainable energy resources [1,2]. In this regard, waste lignocellulosic biomass, which mainly contains cellulose, hemicellulose, and lignin, is considered a promising sustainable resource. Among the value-added molecules, furfural is an important precursor in the generation of biofuels and chemical intermediates It can be readily obtained from hemicellulose by acid-catalyzed cascade hydrolysis and dehydration [4,5]. Owing to its high unsaturation, the selective hydrogenation of furfural

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Conclusion