A synthetic strategy for carbon nanospheres impregnated with highly monodispersed metal nanoparticles

Abstract

N-doped mesoporous carbon nanospheres (N-MCN@M) impregnated with uniformly dispersed noble-metal (Au, Pt, Rh, Ru, Ag, Pd and Ir) nanoparticles are rationally designed and synthesized for hydrogenation reactions. This facile and generally applicable synthetic strategy ensured confinement of the noble-metal nanoparticles within different carbon morphologies, including mesoporous spheres, hollow particles and core-shell particles. High loading of the noble-metal nanoparticles from 8 to 44% was accomplished by tuning the initial concentration of metal salts. Even at very high loadings (440 wt%), a homogeneous dispersion of uniform metal nanoparticles throughout the carbon nanostructures was achieved. The proposed synthesis is also well suited for the fabrication of carbon spheres loaded with bimetallic nanoparticles (AuPt, AuRh and PtRh). Examination of these metal-loaded carbon particles as catalysts for the hydrogenation of benzaldehyde gave 100% selectivity toward carbonyl group at room and higher reaction temperatures. The outstanding performance of Au nanoparticles gave an unprecedented turn over frequency 2-4 times greater than those of Pt nanoparticles with the same size, loading and support.

Bimetallic AuRh nanodendrites consisting of Au icosahedron cores and atomically ultrathin Rh nanoplate shells: synthesis and light-enhanced catalytic activity

“…[1][2][3][4][5][6] The physical and chemical properties of bimetallic noble metal nanostructures not only depend on their chemical compositions but also are related to their morphologies. [4][5][6][7][8][9] In general, bimetallic nanostructures display remarkably improved catalytic activity and selectivity compared with the corresponding monometallic nanocrystals due to the strong ensemble and ligand effects between the different components (that is, geometrical and electronic effects). [4][5][6][7]9 Meanwhile, noble metal nanodendrites with branched arms are attracting tremendous attention for the catalytic applications due to their large surface area, unusual interconnected and porous structure and abundance of low-coordination atoms at steps and corners.…”

Confining Sub‐Nanometer Pt Clusters in Hollow Mesoporous Carbon Spheres for Boosting Hydrogen Evolution Activity

“…These drawbacks might be overcome by using catalyst supports with delicately designed nanostructure. For example, hollow mesoporous carbon spheres (HMCSs) would be attractive as catalyst supports comparing to conventional carbon supports . Such a structure could provide large accessible surface to support clusters and facilitate ion/mass transport in the electrode.…”

Nanoengineering Carbon Spheres as Nanoreactors for Sustainable Energy Applications

“…c) TEM image of Au loaded carbon spheres. TEM image: Reproduced under the terms of the CC‐BY Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/) . Copyright 2016, Springer Nature.…”

“…Many methods have been developed for the deposition of metal nanoparticles onto carbon spheres through one‐pot synthesis or post‐synthesis modification in the presence of metal salts. Several methods including directly impregnating metal salts with carbon precursor, spray pyrolysis, hydrothermal synthesis, microwave synthesis, and CVD have been used for the preparation of carbon spheres decorated with metal nanoparticles . The most popular way to achieve metal‐loaded carbon spheres is to impregnate carbon spheres with metal salts, followed by thermal or chemical reduction process.…”