Regenerable Subnanometer Pd Clusters on Zirconia for Highly Selective Hydrogenation of Biomass-Derived Succinic Acid in Water

Abstract

Abstract:The size of metal particles is an important factor to determine the performance of the supported metal catalysts. In this work, we report subnanometer Pd clusters supported on zirconia by the microwave-assisted hydrothermal method. The presence of subnanometer Pd clusters on the zirconia surface was confirmed by two-dimensional Gaussian-function fits of the aberration-corrected high-angle annual dark-field images. These subnanometer Pd catalysts exhibit high catalytic performance for the hydrogenation of biomass-derived succinic acid to γ-butyrolactone in water and avoid the formation of overhydrogenated products, such as 1,4-butanediol and tetrahydrofuran. The catalyst with an ultra-low Pd loading of 0.2 wt. % demonstrated high selectivity (95%) for γ-butyrolactone using water as a solvent at 473 K and 10 MPa. Moreover, it can be reused at least six times without the loss of catalytic activity, illustrating high performance of the small Pd clusters.

Hydrogenation of Carboxylic Acids, Esters, and Related Compounds over Heterogeneous Catalysts: A Step toward Sustainable and Carbon-Neutral Processes

“…A similar conclusion on Cu-based catalyst was also reported by Hwang, Chang, and co-workers, 236 who observed that for the hydrogenation of dimethyl succinate, Cu nanoparticles with size of 11 nm gave 93% yield of THF (Table 4, entry 35), much higher than that over 33 nm Cu nanoparticles (20% selectivity at 100% conversion). In 2016, Chen and co-workers 214 investigated the effect of Pd loading and dispersion on SA hydrogenation activity. The TOFs remained almost unchanged when Pd particle sizes decreased to the atomic dispersion level, but a drastic decrease of TOF was observed with increasing Pd loading.…”