Mignoli, T. R.Hewer, T. L. R.Alves, R. M. B.Schmal, M....
9页
查看更多>>摘要：In this work we prepared Cobalt-Lanthanum oxide supported on reduced graphene oxide (rGO) for the water-gas shift reaction (WGSR). The reduced graphene oxide support was synthesized and then impregnated with cobalt (15% wt.) and lanthanum (10% wt.) nanoparticles using the precipitation-deposition method. The textural and morphologic characterization techniques confirmed that both catalysts presented small and high-dispersed nanoparticles and high surface area. The support structure was also preserved, according to XRD and Raman analyses. XPS results showed that La promotion increased the concentration of Co2+ species, and the reducibility. CO conversions and H-2 yields were close to thermodynamic equilibrium values above 400 degrees C. The WGS catalytic test results ratified that the La promoter improved significantly the H-2 yield above 275 degrees C and inhibited methane formation at low temperatures. Results show that La2O3 react with H2O and subsequently with CO2 increasing H-2 formation.
Wang, ShanZhu, JunjiangCarabineiro, Sonia A. C.Xiao, Ping...
10页
查看更多>>摘要：A selective etching method was reported to prepare porous LaCoO3 perovskite for catalytic combustion of ethyl acetate (EA). The porous LaCoO3 was obtained by selectively etching of in-situ formed La2O3 particles with acetic acid (HAc) from a pre-synthesized LaCoO3-La2O3 composite. XRD, N-2 physisorption, ICP-OES, TEM, XPS, H-2-TPR and O-2-TPO showed that the etching of La2O3 with HAc not only generated surface La defects, but also improved the porosity, the exposure of active sites and the redox properties of the material. Therefore, the porous LaCoO3 can contact and activate the reactants efficiently, accelerating the reaction rate. LCO2.0-30, prepared with La/Co molar ratio of 2.0 and etched for 30 min, was the most active catalyst even in presence of H2O, with 100% EA conversion at 220 degrees C, due to its abundant porosity, surface active sites and strong reducibility. A possible reaction mechanism for EA combustion conducted on porous LaCoO3 perovskite was proposed.
查看更多>>摘要：Production of gamma-valerolactone (GVL) from biomass-derived platform levulinic acid (LA) via catalytic transfer hydrogenation (CTH) over renewable lignosulfonate-derived catalyst is reported herein. Lignosulfonate-derived catalysts were prepared by assembled Zr-metals with sodium lignosulfonate (LigS) derived from the industry paper waste. The resulting Zr-LigS catalyst exhibited excellent catalytic performance in 92.5% GVL yield under mild conditions. With the combination of detail catalyst characterizations, catalytic performance of the Zr-LigS catalyst, in-situ ATR-FTIR and poisoning experiments, the hydrothermal treatment of Zr4+ and LigS resulted in the formation of basic sites, which contributed significantly to the CTH reaction. Kinetic experiments demonstrated that the activation energy was as low as 41.9 kJ/mol. Furthermore, isotopic labeling experiments suggested that the beta-H in isopropanol is transferred to the C=& nbsp;O bond of LA by the formation of six-membered intermediates on the basic sites, which is the rate-determining step.
NSTL
Elsevier