Product Selectivity Controlled by Zeolite Crystals in Biomass Hydrogenation over a Palladium Catalyst

Abstract

This work delineates the first example for controlling product selectivity in metal-catalyzed hydrogenation of biomass by zeolite crystals. The key to this success is to combine the advantages of both Pd nanoparticles (highly active sites) and zeolite micropores (controllable diffusion of reactants and products), which was achieved from encapsulation of the Pd nanoparticles inside of silicalite-I zeolite crystals as a core-shell structure (Pd@S-1). In the hydrogenation of biomass-derived furfural, the furan selectivity over the Pd@S-1 is as high as 98.7%, outperforming the furan selectivity (5.6%) over conventional Pd nanoparticles impregnated with S-1 zeolite crystals (Pd/S-1). The extraordinary furan selectivity in the hydrogenation over the Pd@S-1 is reasonably attributed to the distinguishable mass transfer of the hydrogenated products in the zeolite micropores.

Controllable cyanation of carbon-hydrogen bonds by zeolite crystals over manganese oxide catalyst

“…1. Our strategy to synthesize MnO x @S-1 catalyst is based on the solvent-free process recently developed for synthesizing zeolites, which facilitates fixing metallic nanocrystals into zeolite crystal for constructing host–guest structure32. The MnO x @S-1 catalyst was synthesized from grinding the solid raw material mixture of tetrapropylammonium hydroxide (TPAOH) and hybrid SiO 2 -MnO x , followed by thermal treatment at 180 °C for 2 days (Fig.…”

Supported Metal Catalysts for Total Hydrogenation of Furfural and 5-Hydroxymethylfurfural

“…One of typical side reactions over Pd catalysts is decarbonylation (furfural to furan; HMF to FOL) which is dominant at high temperature (e.g. 393 K) 29), 30) . Pd catalysts can be selective in total hydrogenation at low temperature.…”

Directing Reaction Pathways through Controlled Reactant Binding at Pd–TiO2 Interfaces

“…[4][5][6][7][8] Thei mportance of interfacial sites in catalysis suggests that catalyst design should emphasize novel methods for tailoring these interfaces that go beyond using the oxide as as imple catalyst carrier. While encapsulated structures have been applied to enhance the stability of metal NPs [11][12][13][14] or improve the selectivity and/or activity for selective oxidation, [15][16][17] hydrogenation, [18][19][20] and decarbonylation, [21] HDO provides an important probe reaction for testing their utility for reactions that occur at metal/oxide interfaces.M oreover,t he unique geometry of the sites in an encapsulated structure could result in an ew way to control interfacial properties via biasing the reactant binding orientations.F or aromatic alcohols,flat-lying adsorbates are prone to decarbonylation and ring hydrogenation while upright adsorption geometries favor HDO. While encapsulated structures have been applied to enhance the stability of metal NPs [11][12][13][14] or improve the selectivity and/or activity for selective oxidation, [15][16][17] hydrogenation, [18][19][20] and decarbonylation, [21] HDO provides an important probe reaction for testing their utility for reactions that occur at metal/oxide interfaces.M oreover,t he unique geometry of the sites in an encapsulated structure could result in an ew way to control interfacial properties via biasing the reactant binding orientations.F or aromatic alcohols,flat-lying adsorbates are prone to decarbonylation and ring hydrogenation while upright adsorption geometries favor HDO.…”