Increased Hydrogenation Rates in Pd/La-Al₂O₃ Catalysts by Hydrogen Transfer O(-La) Sites Adjacent to Pd Nanoparticles

Abstract

In this study, a simple bottom-up synthesis is presented to introduce atomically dispersed La into Al 2 O 3 followed by the addition of Pd to prepare a microspherical Pd/La-Al 2 O 3 catalyst with potential for hydrogenation applications. The Pd/La-Al 2 O 3 catalyst displays enhanced activity for a number of hydrogenation reactions and functional groups, for example, C�O, C�C, C�N, and aromatic rings. Incorporation of O(-La) sites adjacent to Pd nanoparticles (NPs) is suggested to reversibly transfer and store catalytically active hydrogen at the O(-La) site. A kinetic analysis of 2-ethylanthraquinone (EAQ) hydrogenation shows that the H 2 reaction order drops from one for Pd/Al 2 O 3 to zero for Pd/La-Al 2 O 3 , while the EAQ order remains unchanged. Incorporation of isolated O(-La) sites adjacent to the Pd NPs provides a feasible strategy for the design of high-efficiency hydrogenation catalysts and has important implications for the development of the commercial hydrogenation process.

GuaiacolHDOon La‐modified Pt/Al2O3: Influence of rare‐earth loading

“…Indeed, decreased order (from 1 to 0) in the H 2 reaction during ethylanthraquinone hydrogenation on Pd/Al 2 O 3 after La‐addition was recently reported. [ 93 ] Corresponding investigations will be the subject of upcoming reports.…”

Dual Scale Hydrogen Transfer Bridge Construction for Biomass Tandem Reductive Amination

“…In sharp contrast, the Schiff base conversion rate increases linearly with the incremental hydrogen pressure over the Ru/MgAlO x catalyst (Figure J), showing the characteristics of a first-order reaction. The reaction order with respect to hydrogen decreases from one to zero by the Ru/Ga 2 O 3 /MgAlGaO x catalyst, which demonstrated experimentally that construction of a dual-scale hydrogen bridge can facilitate H* spillover adequately to the support and thus provide vast H* to participate in the reaction on the Ru/Ga 2 O 3 /MgAlGaO x catalyst . Furthermore, the activation energy is also determined and compared (Figure K).…”

“…The reaction order with respect to hydrogen decreases from one to zero by the Ru/Ga 2 O 3 /MgAlGaO x catalyst, which demonstrated experimentally that construction of a dual-scale hydrogen bridge can facilitate H* spillover adequately to the support and thus provide vast H* to participate in the reaction on the Ru/Ga 2 O 3 /MgAlGaO x catalyst. 32 Furthermore, the activation energy is also determined and compared (Figure 2K). The apparent activation energies for the key process of Schiff base to furfurylamine over Ru/Ga 2 O 3 /MgAlGaO x catalyst was 26.94 kJ/mol, which was lower than the 33.75 kJ/mol over Ru/ MgAlO x catalyst, suggesting that the Ru/Ga 2 O 3 /MgAlGaO x catalyst showed higher intrinsic activity due to the prominent improvement of hydrogen spillover capacity.…”

Tuning the Surface Wettability of Pd/COFs for Selective Hydrogenation

“…In general, the catalytic performance of metal NPs is greatly affected by their surface electronic and geometric structures, which could be tuned by size, morphology, foreign atom doping and the type of supports. [2][3][4][5][6][7] In addition to active sites, the surface wettability of supports also greatly affects the selectivity and activity of metal NPs by influencing the diffusion and adsorption of reactants, intermediates and products around the active sites. [8,9] More importantly, the enrichment of reactants near active sites is one of the unique properties of enzymes.…”

“…The development of highly selective and active metal catalysts has attracted great attention in the field of heterogeneous catalysis. In general, the catalytic performance of metal NPs is greatly affected by their surface electronic and geometric structures, which could be tuned by size, morphology, foreign atom doping and the type of supports [2–7] . In addition to active sites, the surface wettability of supports also greatly affects the selectivity and activity of metal NPs by influencing the diffusion and adsorption of reactants, intermediates and products around the active sites [8,9] .…”