Enhancing the catalytic activity of Ru NPs deposited with carbon species in yolk–shell nanostructures

Abstract

The synthesis of metal NPs with a well-defined size, shape and composition provides opportunities for tuning the catalytic performance of metal NPs. However, the presence of a stabilizer on the metal surface always blocks the active sites of metal NPs. Herein, we report an efficient method to remove the stabilizer on the metal surface via H 2 pyrolysis with Ru-poly(amindoamine) encapsulated in silica-based yolk-shell nanostructures as an example. The CO uptake amount of Ru NPs increases sharply after H 2 pyrolysis, indicating that the exposure degree of Ru NPs is increased. No aggregation of the colloidal Ru NPs occurs after H 2 pyrolysis, which could be mainly assigned to the protection effect of C and N species formed on Ru NPs. The overall activity of Ru NPs in the yolk-shell nanostructure after the pyrolysis could reach as high as 20 300 mmol per mmol Ru per h in the hydrogenation of toluene, which is much higher than that of most reported Ru-based solid catalysts. It was found that the yolkshell nanostructure could efficiently prevent the leaching of Ru NPs during the catalytic process. Ru NPs in the yolk-shell nanostructure could also catalyze the hydrogenation of benzoic acid and Levulinic acid with high activity and selectivity.

Synthesis of a highly active amino‐functionalized Fe3O4@SiO2/APTS/Ru magnetic nanocomposite catalyst for hydrogenation reactions

“…As shown in Figure b, the core–shell structure of Fe 3 O 4 @SiO 2 can be clearly seen, with a uniform silica shell deposited on the Fe 3 O 4 particles with a thickness of ca 28 nm. As illustrated in Figure c, numerous monodispersed Ru nanoparticles (2.5 nm) were uniformly decorated on the surface of Fe 3 O 4 @SiO 2 , which was mainly due to the amino groups effectively preventing the aggregation of the Ru nanoparticles, ensuring that the Ru nanoparticles were not easily lost when reused in liquid‐phase catalytic reactions . Figure e shows that when no affinity ligands were used, although many of the Ru nanoparticles were located on the Fe 3 O 4 @SiO 2 particle surface, some major aggregates of Ru nanoparticles were also obviously observed on the surface of Fe 3 O 4 @SiO 2 .…”

Advanced Carbon‐Based Nanocatalysts and their Application in Catalytic Conversion of Renewable Platform Molecules

“…In many catalytic reactions, internal active species would directly affect the catalytic performance of carbon‐encapsulated metal catalysts [128,129,132,133,137–145,149] . Zhao and co‐workers prepared Co nanoparticles (NPs) with Co−N x active sites confined by nitrogen‐doped carbon nanotubes through pyrolyzing ZIF‐67 [128] .…”

Facile synthesis of urchin-like RuCu and hollow RuCuMo nanoparticles and preliminary insight to their formation process by cyclic voltammetry

“…As an important platinum-group metal, Ru is comparatively cheaper and has been widely used in many important reactions such as CO oxidation, 12 selective hydrogenation, 13 and dehydrogenation of ammonia borane. 14 Despite successful synthesis of Ru NPs with well-dened size and morphology, [15][16][17][18][19][20][21] the synthesis of Rubased NPs received limited success. 22,23 A possible reason for this is that Ru is too active to be stable in oxidative environment.…”