Enhanced catalytic performance of Cu-and/or Mn-loaded Fe-Sep catalysts for the oxidation of CO and ethyl acetate

The Fe-modi fied sepiolite-supported Mn–Cu mixed oxide(Cux Mny/Fe-Sep) catalysts were prepared using the co-precipitation method.These materials were characterized by means of the XRD,N_2 adsorption–desorption,XPS,H_2-TPR,and O_2-TPD techniques,and their catalytic activities for CO and ethyl acetate oxidation were evaluated.The results show that catalytic activities of the Cux Mny/Fe-Sep samples were higher than those of the Cu1/Fe-Sep and Mn2/Fe-Sep samples,and the Mn/Cu molar ratio had a distinct in fluence on catalytic activity of the sample.Among the Cux Mny/Fe-Sep and Cu1Mn2/Sep samples,Cu1Mn2/Fe-Sep performed the best for CO and ethyl acetate oxidation,showing the highest reaction rate and the lowest T50 and T90 of 4.4×10^(-6) mmol·g-1·s-1,110,and 140 °C for CO oxidation,and 1.9×10^(-6) mmol·g-1·s-1,170,and210 °C for ethyl acetate oxidation,respectively.Moreover,the Cu1Mn2/Fe-Sep sample possessed the best lowtemperature reducibility and the lowest temperature of oxygen desorption as well as the highest surface Mn^(4+)/Mn^(3+) and Cu^(2+)/CuO atomic ratios.It is concluded that factors,such as the strong interaction between the Cu or Mn and the Fe-Sep support,good low-temperature reducibility,and good mobility of chemisorbed oxygen species,might account for the excellent catalytic activity of Cu1Mn2/Fe-Sep.

Surface Coordination Decouples Hydrogenation Catalysis on Supported Metal Catalysts

Supported metal catalysts integrating advantages of catalytic hydrogenation and stoichiometric reduction are highly desirable for the green production of fine chemicals.Decoupling catalytic hydrogenation into H_(2)activation and selective reduction taking place at different locations is expected to provide an effective strategy to fabricate such catalyst systems.Herein,we report a decoupled hydrogenation system by modifying Pt catalysts supported on reducible In2O3 with ethylenediamine(EDA).The system exhibits good catalytic performance in oximes production from nitroalkanes,an industrially important reaction,by employing H_(2).Systematic studies demonstrate that the surface coordination of EDA on Pt is crucial to passivate the Pt surface from nitro hydrogenation without inhibiting H_(2)activation.The activated H_(2)species can then transfer and reduce the In_(2)O_(3)support in situ to generate sustainable stoichiometric reducing agents for the chemoselective reduction of nitroalkanes.Based upon the mechanistic understanding,a sustainable strategy for the production of oximes has been successfully fabricated.