PdC_x nanocrystals with tunable compositions for alkyne semihydrogenation

Abstract

A novel and efficient approach has been reported for the preparation of PdCx nanocatalysts with tunable compositions for enhanced alkyne semihydrogenation.

Gold catalysts containing interstitial carbon atoms boost hydrogenation activity

“…The carbonization step with metal species is analogous to the growth of carbon nanotubes by catalytic chemical vapor deposition 24 . Carbon atoms deposit on the transition metal surface such as iron and palladium, and diffuse into the lattice 25 . Schlögl and coworkers reported the formation of interstitial C atoms in a Pd catalyst during the hydrogenation of alkyne, which showed significant promotion in the selectivity for olefins 26 .…”

Seed‐mediated Growth of AlloyedAg‐PdShells toward Alkyne Semi‐hydrogenation Reactions under Mild Conditions†

“…Meanwhile, Ag nanoplates as growth substrates could suppress the formation of β‐palladium hydride (β‐PdH) phase, which has been proven to be the key factor for forming alkanes. [ 8,38,61 ]…”

“…[ 5‐6 ] In addition, the Pd nanoparticles usually undergo a surface reconstruction that leads to the particle sintering during calcination and reactions and subsequently decreases their overall activities. Conventional approaches for enhancing the catalytic selectivity and stability of Pd targeting alkenes via the semi‐hydrogenation include controlling the shape of palladium nanocrystals, [ 7‐8 ] preparing isolated single‐atom Pd catalysts, [ 9‐12 ] using various supports ( e.g , TiO 2 , [ 13 ] Ni(OH) 2 , [ 14 ] mpg‐C 3 N 4 , [ 15 ] CeO 2 , [ 16‐17 ] Al 2 O 3 , [ 18 ] SiO 2 , [ 19 ] Fe 3 O 4 , [ 20 ] C, [ 21‐22 ] N‐CNT, [ 23 ] HT, [ 24 ] COF [ 25 ] and MOF [ 26‐31 ] materials), doping second elements ( e.g , Pb, [ 8,32‐33 ] Zn, [ 34‐35 ] S, [ 36 ] P, [ 37 ] C, [ 38‐39 ] Ga, [ 40‐41 ] In [ 10,42 ] ), preparing nanocomposites ( e.g , CuFe 2 O 4 , [ 43 ] Cu 2 O, [ 44 ] ZnO [ 45 ] ) and using organic modifiers (modifying elements such as N, [ 46‐51 ] S, [ 51‐55 ] or P [ 55 ] ) to poison the active sites. Nearly all these methods could increase the selectivity of Pd as a semi‐hydrogenation catalyst by regulating the electronic state (ligand effect) [ 8,12,15,36 ] or/and separating the active sites of Pd (ensemble effect).…”

Decreasing the coordinated N atoms in a single-atom Cu catalyst to achieve selective transfer hydrogenation of alkynes

“…Benefitting from the superior reusability, a few heterogeneous catalysts have been applied in this transformation. [41][42][43][44][45] However, these heterogeneous catalysts are mainly based on the noble metal with selectivity issues or suffering from harsh reaction conditions (high temperature and high pressure of H 2 ). It is highly desirable to develop the more abundant non-noble metal based heterogeneous catalysts for such reaction with good selectivity under mild conditions.…”