Highly dispersed copper nanoparticles supported on silica were successfully prepared by a simple and convenient precipitation−gel technique, and their physicochemical properties and activity were compared to those of a catalyst prepared by the conventional impregnation method. As a consequence of the preparation method, the texture (BET), dispersion (dissociative N2O adsorption), morphology (TEM), reduction behavior (TPR, XRD), state of copper species (XPS), and catalytic performance (glycerol hydrogenolysis) differ between samples. Both samples showed high selectivity (>98%) toward 1,2-propanediol in glycerol reaction. Because of a much smaller particle size, a higher dispersion of copper species with a strong metal−support interaction, and more resistance to sintering, the CuO/SiO2 catalyst prepared by precipitation–gel method presented a much higher activity and remarkably better long-term stability in glycerol reaction than did the catalyst prepared by impregnation method. The catalytic behavior of calcined and reduced samples and the structure changes of these samples after reaction allow the understanding of the stability toward sintering as well as the possible mechanism of the reaction.

In this work, we report a novel and facile procedure for a one-pot preparation of palladium nanoparticle catalysts supported on porous N-doped carbon (Pd@CNT) by direct carbonization of palladium-N-heterocyclic carbene coordination polymer (P-Pd-NHC). This method could be conveniently extended to the synthesis of the Ni and alloy (Pd x Ni y ) nanoparticle catalysts (Ni@CN800, Pd x Ni y @CN800). The treatment temperature played an important role on the growth and properties of the resultant M@CNT, wherein M@CN800 carbonized at 800 °C showed well-monodispersed metal nanoparticles (MNPs), graphene-like layers of the N-doped carbon supports, and strong interaction between MNPs and the support. Pd@CN800 displayed high efficiency and stable recyclability toward the domino carbonylative synthesis of pyrazole derivatives. Interestingly, its catalytic performance has been even higher than that of the representative PdCl2(PPh3)2 within six runs.

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a Copper-silica nanocomposite catalysts with uniform Cu dispersion prepared by precipitation-gel method have been disclosed to be highly efficient in the heterogeneous catalysis of hydrogenation of CO2-derived cyclic carbonates, providing an indirect but practical approach for the transformation of CO2 to methanol with the co-production of diols under relatively mild conditions. The catalysts possessed remarkable stability in both batch and fixed-bed continuous flow reactors especially after promotion with B2O3. The reaction was found to depend sensitively on the Cu particle sizes, the surface acid-basicity and Cu valence of the catalysts. The synergetic effect between balanced Cu 0 and Cu + sites was considered to play a critical role for attaining high yields of methanol and diols.

Hydrogenolysis of biomass-derived furfuryl alcohol to 1,2-pentanediol and 1,5-pentanediol with high yield (~80%) could be achieved over a simple but efficient non-precious Cu–Mg3AlO4.5 bifunctional catalyst at mild conditions.

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