Supported Pd nanoparticle catalysts with high activities and selectivities in liquid-phase furfural hydrogenation

• Published in: Fuel (Guildford) 2018-08, Vol.226, p.607-617
• Main Authors: Nguyen-Huy, Chinh, Kim, Ji Sun, Yoon, Sinmyung, Yang, Euiseob, Kwak, Ja Hun, Lee, Man Sig, An, Kwangjin
• Format: Article
• Language: English
• Subjects: Alcohols; Aluminum oxide; Catalysts; Catalytic converters; Chemical elements; Chemical reduction; Chromium; Citric acid; Dispersion; Fluids; Furfural; Furfural hydrogenation; Furfuryl alcohol; Hydrogenation; Liquid phases; Nanoparticles; Organic chemistry; Palladium; Pd nanoparticle; Silica; Silicon dioxide; Sodium; Sodium citrate; Supported catalyst; Tetrahydrofuran; Thermal reduction
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2018.04.029

[Display omitted] •Ultrafine Pd NPs deposited on carbon, silica, and alumina supports were prepared.•The chemical reduction, impregnation, and capillary inclusion of the Pd NPs were used.•The catalysts were evaluated in the liquid-phase hydrogenation of furfural.•The 5 wt% Pd/C catalysts possessed highly dispersed small Pd nanoparticles.•High conversions and selectivities towards tetrahydrofurfuryl alcohol were obtained. Highly dispersed and ultrafine Pd nanoparticles (NPs) deposited on carbon, silica, and alumina supports were prepared by chemical reduction (CR) using sodium borohydride, in the presence of trisodium citrate as a stabilizer. For comparison, supported Pd catalysts were also prepared through impregnation followed by thermal reduction (TR) and capillary inclusion of the colloidal Pd NPs (CI). The activities and selectivities of the prepared catalysts were evaluated in the liquid-phase furfural (FAL) hydrogenation reaction under 20 bar H2 at 180 °C. Under these conditions, FAL was converted via two distinct pathways to produce either furan via decarbonylation or furfuryl alcohol (FA) via aldehyde hydrogenation. Subsequently, furan and FA were converted to tetrahydrofuran and tetrahydrofurfuryl alcohol (THFA), respectively, via ring hydrogenation. 2-Methylfuran was also produced from the hydration of FAL. To verify the efficiency of the preparation methods, the size of the Pd NPs, the degree of metal dispersion, and the type of supports were correlated with the catalytic conversions and selectivities of FAL hydrogenation. It was confirmed that the 5 wt% Pd/C catalysts possessed highly dispersed small Pd NPs with large metallic Pd surface areas, which resulted in high conversions and selectivities towards THFA in the FAL hydrogenation reaction compared to conventional supported catalysts.