A novel Fe₃O₄@nSiO₂@NiPd–PVP@mSiO₂ multi-shell core–shell nanocomposite for cinnamic acid hydrogenation in water

Abstract

A novel Fe3O4@nSiO2@NiPd-PVP@mSiO2 multi-shell core-shell nanocomposite, with a Brunauer-Emmet-Teller surface area as high as 304.5 m 2 /g, has been prepared by the combination of a modified Stöber method, impregnation reduction and surfactant-templating method. It has a multi-shell structure with ferroferric oxide as core, an inner nonporous silica shell, polyvinylpyrrolidone (PVP) dispersed Ni and Pd active species, and an outer mesoporous silica shell in sequence, as confirmed by transmission electron microscopy and nitrogen adsorption-desorption. It showed an excellent catalytic performance in the selective hydrogenation of cinnamic acid to hydrocinnamic acid under relatively mild reaction conditions and can be recycled efficiently. Furthermore, it also exhibited good catalytic activity and stability in the hydrogenation of a number of unsaturated substrates in water. It was demonstrated that addition of small amounts of Pd can markedly improve its activity. The combination of PVP and the outer mesoporous silica shell can not only disperse the active species but also suppress their loss or aggregation during the reaction, accounting for its good stability in water.

Actively Targeted Deep Tissue Imaging and Photothermal‐Chemo Therapy of Breast Cancer by Antibody‐Functionalized Drug‐Loaded X‐Ray‐Responsive Bismuth Sulfide@Mesoporous Silica Core–Shell Nanoparticles

“…Hence, the mPS shell structure was obtained after the PVP molecules were washed away from the NPs finally. [24] …”

Noncovalently functionalized carbon nanotubes immobilized Fe–Bi bimetallic oxides as a heterogeneous nanocatalyst for reduction of nitroaromatics

“…As present in the XRD patterns (Fig. 3 [34,55]. The crystalline of the catalyst was not good enough, and there was no obvious difference between the as-prepared catalyst and the ten-times-used one.…”

“…To extend the reusability and the lifetime of the catalysts, one of the ideal strategies is to anchor metallic nanoparticles onto some appropriate supporters [34]. Thereby the aggregation of metals can be effectively prevented, thus the nanoparticles can be recovered and maintain their activity [35].…”

A Bifunctional Multishell Catalyst with a Wide Operating Temperature Window for NOx Abatement by Ammonia-Selective Catalytic Reduction

“…The multishell particles possess superior physicochemical properties, such as rapid mass transfers and a high degree of nanosized particle dispersion . Additionally, the catalyst also exhibits properties similar to those of bifunctional catalysts. , Therefore, a possible way to get the NH 3 –SCR catalysts with a wide operating temperature range is to combine the advantages of the superior low-temperature activity of Mn-based catalyst and high-temperature activity of V-based catalyst in a multishell structure comprising different functional shells. In the multishell-structured NH 3 –SCR catalyst system for NO x abatement, the external shell mainly contains vanadium-based catalyst, and the inner shells mainly contain Mn–Co oxide catalyst.…”