Zeolite‐Encaged Pd–Mn Nanocatalysts for CO₂ Hydrogenation and Formic Acid Dehydrogenation

Abstract

AC O 2-mediated hydrogen storage energy cycle is ap romising wayt oi mplement ah ydrogen economy,b ut the exploration of efficient catalysts to achieve this process remains challenging.H erein, sub-nanometer Pd-Mn clusters were encaged within silicalite-1 (S-1) zeolites by al igand-protected method under direct hydrothermal conditions.T he obtained zeolite-encaged metallic nanocatalysts exhibited extraordinary catalytic activity and durability in both CO 2 hydrogenation into formate and formic acid (FA) dehydrogenation backt oC O 2 and hydrogen. Thanks to the formation of ultrasmall metal clusters and the synergic effect of bimetallic components,t he PdMn 0.6 @S-1 catalyst afforded af ormate generation rate of 2151 mol formate mol Pd À1 h À1 at 353 K, and an initial turnover frequency of 6860 mol H 2 mol Pd À1 h À1 for CO-free FA decomposition at 333 Kw ithout any additive.B oth values represent the top levels among state-of-the-art heterogeneous catalysts under similar conditions.This work demonstrates that zeoliteencaged metallic catalysts hold great promise to realizeC O 2mediated hydrogen energy cycles in the future that feature fast charge and release kinetics.

Silica-Supported PdGa Nanoparticles: Metal Synergy for Highly Active and Selective CO2-to-CH3OH Hydrogenation

“…Between 2200 and 1200 cm –1 ( Figure 5 b), three kinetically distinct bands are observed, with maxima at 2085, 1920, and 1588 cm –1 , which are assigned to terminal CO bound to Pd (μ 1 -CO Pd ), bridging CO species bound to Pd (μ n -CO Pd ), and the OCO asymmetric stretch of formate species bound to metallic sites, respectively. 37 In contrast to observations from ex situ experiments, both surface carbonyl species and formate species are observed in reaction conditions. Consistent with observations from ex situ experiments, methoxy species are the dominant surface oxygenate species.…”

Facilitating Pt−WOx Species Interaction for Efficient Glycerol Hydrogenolysis to 1,3‐Propanediol

“…However, Pt white‐line intensity for Pt/WO x / α ‐Al 2 O 3 was lower than that for Pt/ α ‐Al 2 O 3 , suggesting that the Pt species in Pt/WO x / α ‐Al 2 O 3 hold a higher electron density than that in Pt/ α ‐Al 2 O 3 catalyst. The introduction of W species induced charge transfer from WO x to Pt and form an electron‐enriched surface of Pt clusters in Pt/WO x / α ‐Al 2 O 3 catalyst [49] . XPS, H 2 ‐TPR, and CO‐FTIR characterizations also illustrated that the introduction of WO x enhanced the electronic interaction between Pt and WO x , herein, we ascribed the Pt‐O bond in Pt/WO x / α ‐Al 2 O 3 to the formation of Pt−O−WO x interface.…”

Silica-supported PdGa Nanoparticles: Metal Synergy for Highly Active and Selective CO2-to-CH3OH Hydrogenation

“…Between 2200 cm -1 and 1200 cm -1 , three kinetically distinct bands are observed, with maxima at 2085 cm -1 , 1920 cm -1 and 1588 cm -1 , which are assigned to terminal CO bound to Pd (μ 1 -CO Pd ), bridging CO species bound to Pd (μ n -CO Pd ), and the OCO asymmetric stretch of formate species bound to metallic sites, respectively. 34 In contrast to observations from ex situ experiments, both surface carbonyl species and formate species are observed in reaction conditions. Consistent with observations from ex situ experiments, methoxy species are the dominant surface oxygenate species.…”