Acceleration of the semi-hydrogenation of alkynes over an N-doped porous carbon sphere-confined ultrafine PdCu bimetallic nanoparticle catalyst

Selective hydrogenation of alkynes to obtain alkenes is a key reaction in petrochemical and fine chemical industries. However, the development of stable and highly selective catalysts with uniformly dispersed active sites is still immensely challenging for the semi-hydrogenation of alkynes. In this study, N-doped porous carbon nanospheres (NPCNs) were synthesized by the nanoemulsion self-assembly and subsequently carbonization method. Ultrafine PdCu bimetallic nanoparticles (NPs) were uniformly dispersed and immobilized on NPCNs. The obtained PdCu/NPCNs catalyst exhibited an open framework and abundant active sites originating from ultrafine PdCu NPs. In the semi-hydrogenation of alkynes, the PdCu/NPCNs catalyst exhibited a remarkable performance and stability, outperforming most of the classical catalysts. The excellent performance was related to the introduction of a secondary metal Cu, which can regulate the electronic state of Pd active sites to further enhance the hydrogenation activity and selectivity. Hence, the facile approach reported herein may be useful for constructing highly dispersed bimetallic NP-based catalysts for selective hydrogenation of alkynes in the petrochemical industry.

Controlling the selectivity of bimetallic platinum–ruthenium nanoparticles supported on N-doped graphene by adjusting their metal composition

Bimetallic platinum–ruthenium nanoparticles supported on N-doped graphene as chemoselective hydrogenation catalysts.

Synthesis of ultrathin Ni nanosheets for semihydrogenation of phenylacetylene to styrene under mild conditions

The synthesis of ultrathin metal nanosheets (NSs) attracts broad scientific and technological interest, and it still remains a challenge for non-noble metals like nickel due to their intrinsic cubic symmetry and high surface energy. Herein, we report a NiO intermediated solvothermal method towards the synthesis of ultrathin Ni NSs (thickness < 3 nm) using N,N-dimethylformamide as the solvent and n-butylamine as the shape controlling reagent. The growth of the ultrathin Ni NSs follows an intermediate mechanism which was proved by the results obtained by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray absorption spectra (XAS) and X-ray photoelectron spectroscopy (XPS). Under solvothermal conditions, the nickel acetylacetonate precursor was first reduced to a NiO NS intermediate, then reduction occurred and NiO NSs were reduced to Ni NSs. The synthesized ultrathin Ni NSs predominately in a metallic state showed high selectivity (88.0-92.0%) towards styrene (ST) in the phenylacetylene (PA) semihydrogenation reaction under mild conditions (323 K, 1 atm of hydrogen) in a broad PA conversion range (2.0-98.0%). The low coverage of oxygen atoms on the Ni NS surface is proposed to account for the high ST selectivity, as indicated by density functional theory (DFT) calculations.

Seed-mediated synthesis of bimetallic ruthenium–platinum nanoparticles efficient in cinnamaldehyde selective hydrogenation

The two-step synthesis of small ruthenium–platinum nanoparticles leads to the formation of a core–shell structure. The catalytic results provide supplementary evidence of the core–shell structure.