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

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.

Effect of Carbon Support, Capping Agent Amount, and Pd NPs Size for Bio-Adipic Acid Production from Muconic Acid and Sodium Muconate

“…The main parameters, which affect the NPs' synthesis, are the NPs colloidal concentration, the amount of stabilizer, the amount of reducing agent, and the reduction temperature. Considering catalytic reactions, capping agents (i.e., stabilizers) are considered to have a great impact on the performance of metal NPs due to the hindered access of the substrate on the catalyst surface and their chemical nature [19,20]. In particular, the amount of capping agent and its chemical structure might affect catalyst activity (i.e., acting as promoters) and/or change and eventually control the selectivity in liquid-phase reactions [21].…”

Effect of Pt Particle Size and Phosphorous Addition on Furfural Hydrogenation Over Pt/Al2O3

“…In spite of the TOF increase, the overall catalytic activity decreased upon Pt sintering driven by the loss of active surface (Table 1). In addition, blockage of active sites by irreversible adsorption of reaction intermediates as well as noble metal leaching can also occur during reaction [7]. To determine the causes of deactivation over consecutive furfural hydrogenation runs, pristine Al 2 O 3 -Pt was characterised before and after the durability test.…”

“…Furfural can be converted to furfuryl alcohol (FA) and tetrahydrofurfuryl alcohol (THFA) through selective catalytic hydrogenation (Scheme 1) [6]. FA is especially desirable due to its use in the polymer and fine chemical industries including the manufacture of resins, vitamin C, dispersants, lysine, and lubricants [4,7]. THFA is primarily used as an environmentally friendly solvent since it is degradable, less toxic, and far more stable than unsaturated furan compounds [2, 8,9].…”

Common Reactions of Furfural to scalable processes of Residual Biomass

“…The main reason for the continuous study of furfural hydrogenation is the search for a selective catalyst that controls the reaction route, as well as the degree of furfural hydrogenation. [47]. Industrially, catalysts based on copper and chromium are used, but new catalysts formulations are still of interest.…”

“…Still regarding studies that combined palladium and carbon for catalysts elaboration, a recent paper present a series of 1wt% Pd/C materials as possible catalysts for hydrogenation of FAL in the liquid-phase [47]. These systems were prepared by the sol-immobilization method using different capping agents, like Polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and poly (diallyldimethylammonium chloride) (PDDA).…”