Bao Zhaorigetu

Aerobic Oxidation of Alcohols on Au Nanocatalyst: Insight to the Roles of the Ni–Al Layered Double Hydroxides Support

Au nanoparticles (NPs) supported on Ni–Al layered double hydroxides (LDHs) were shown to be efficient heterogeneous catalysts for the highly selective oxidation of alcohols to the corresponding aldehydes or ketones under base‐free or even solvent‐free conditions with O2 as the sole oxidant. The Au NPs can be uniformly distributed on Ni–Al LDHs support, which is beneficial to the catalytic activity. In addition, the weak Brønsted basic property of the support enables the aerobic oxidation of alcohols under base‐free conditions. More importantly, unlike Al2O3, which is inert, Ni–Al–LDHs are redox‐actively involved in prompting the electron transfer to O2 via the Au nanocatalyst because of the presence of NiII. Both of the basic and the redox properties of Ni–Al–LDHs can be tuned by adjusting the ratio of Ni:Al to achieve the best synergistic effects between Au NPs and the supports. The activity of the obtained Au catalysts was found to be structurally associated with the arrangements of NiO6 and AlO6 octahedra in the surface hydroxide layers which were different from the bulk Ni:Al ratio.

Oxidative dehydrogenation of propane on rare earth vanadates influence of the presence of CO2 in the feed

Abstract The oxidative dehydrogenation of propane on rare earth vanadates is always in competition with the total oxidation of the alkane which leads to the formation of CO 2 and CO. Addition of CO 2 into the feed results in an increased C 3 H 6 selectivity together with a decreased CO formation through the total oxidation of the alkane or the formed alkene. For the tested rare earth vanadates as well as for the niobium promoted catalysts an enhancement of the C 3 H 6 selectivity at isoconversion and thus of the C 3 H 6 yields is observed upon CO 2 addition into the feed.

Synthesis of imines from amines in aliphatic alcohols on Pd/ZrO2 catalyst under ambient conditions

Synthesis of imines from amines and aliphatic alcohols (C1–C6) in the presence of base on supported palladium nanoparticles has been achieved for the first time. The catalytic system shows high activity and selectivity in open air at room temperature. As an example of the isostructural Ln3Sb3Co2O14 (Ln: La, Pr, Nd, Sm—Ho) series with an ordered pyrochlore structure, the La variant is prepared by a citrate complex method employing stoichiometric amounts of La(NO3)3, Co(NO3)2, and Sb tartrate together with citric acid with a metal/citrate molar ratio of 1:2

Heterogeneous recyclable nano-palladium catalyzed amidation of esters using formamides as amine sources

Catalyzed by supported palladium nanoparticles, a decarbonylative amidation reaction between various aryl esters and formamides by C–O bond activation has been developed for the synthesis of amides. The catalyst can be reused and shows high activity after five cycles. The XPS analysis of the catalyst before and after the reaction suggested that the reaction might be performed via a Pd0/PdII/PdIV catalytic cycle that began with Pd0. The hot filtration test strongly suggests that the present reaction would proceed in a heterogeneous manner.

Replacing Pd(OAc)2 with supported palladium nanoparticles in ortho-directed CDC reactions of alkylbenzenes

Supported palladium nanoparticles are used as efficient catalysts for the synthesis of aromatic ketones via cross dehydrogenative coupling reactions of 2-arylpyridines with alkylbenzenes. The catalyst can be reused for five cycles without significantly losing activity. Mechanism research showed that alkylbenzenes were oxidized to their corresponding aldehydes and subsequently coupled with 2-arylpyridines to generate aryl ketones through a Pd0/PdII/PdIV catalytic cycle.

Hydrotalcite-supported Pd–Au nanocatalysts for Ullmann homocoupling reactions at low temperature

Hydrotalcite-supported Pd–Au nanocatalysts were found to be efficient heterogeneous catalysts for Ullmann homocoupling reactions of aryl bromides or chlorides at 25 or 40 °C, which could be due to the ensemble effect and increased electron density of Pd sites on Pd–Au nanoparticles, and the assistant role of the hydrotalcite for the reversion of the catalytic active center, Pd(0).

Relationship between the reducibility and selectivity of CeMox V1-xO4 catalysts by kinetic parameters of TPR

Abstract CeVO4, CeMo0.01V0.99O4 and CeMo0.03V0.97O4 were prepared by co-precipitation method. The addition of molybdenum as promoter shows a positive effect on the catalytic behavior of CeVO4 in oxidative dehydrogenation of propane to propylene. The reduction behaviors of the catalysts were characterized by temperature-programmed reduction. The activation energies of reduction process for the catalysts were obtained at different reduction rates by Kissinger method. The addition of Mo to CeVO4 enhances the selectivity to propylene.