Hierarchical nanostructured spherical carbon with hollow macroporous core in combination with mesoporous shell has been explored to support Pt cathode catalyst with high metal loading in proton exchange membrane fuel cell (PEMFC). The hollow core-mesoporous shell carbon (HCMSC) has unique structural characteristics such as large specific surface area and mesoporous volume, ensuring uniform disp...

in this paper, 4,4ʹ-bipyridinium dichloride  supported sba-15 (sba@bipy2+ 2cl-) was used for the synthesis of dihydropyrimidinones. the synthesized catalyst was characterized by ft-ir spectroscopy, scanning electron microscopy (sem), transmission electron microscopy (tem) and thermogravimetric analysis (tga). this nanocomposite was shown to be an efficient heterogeneous catalyst for the synthes...

a simple and efficient method for the chemoselective 1,1-diacetate protection of aromatic aldehydes with acetic anhydride by using ni2+ supported on hydroxyapatite-core-shell magnetic γ-fe2o3 nanoparticles (γ-fe2o3@hap-ni2+) under solvent free conditions. this method has several advantages, including high yield, short reaction time, simple work-up and recyclable property of the catalyst. the ca...

An efficient synthesis of chromenylphenylpropanone derivatives as warfarine-like analogues was developed by the Michael addition of 4-hydroxycoumarin to α,β-unsaturated compounds in the presence of polyvinylpolypyrrolidone supported antimony(III) chloride (PVPP-SbCl3) as a new polymeric Lewis acid catalyst in chloroform at reflux conditions without formation of 2,4-...

a simple, green and efficient method for synthesis of 2,4,5-trisubstituted imidazoles is described via three-component cyclocondensation of benzil or benzoin, aldehyde and ammonium acetate by using the nano sio2-supported ferric hydrogen sulfate (fhs/sio2), as a catalyst, under solvent-free conditions. the nano sio2 support and catalyst were characterized by x-ray diffraction (xrd), transmissio...

the catalyst pt-ta supported on 7-alumina was prepared by impregnation with solution containing compoundsof ii21k1.0. and ta205 the pt concentration was kept constant at 0.2 vet% while the concentration of thetantalum was 0,4 wt%. the activity and selectivity of catalyst were determined under conditions at 450-500 °cand 15-30 atm.. with molar ratio h2/c[h,e5 and wh=1.5ml/h for converted n-hepta...

Carbon capsules with hollow core and mesoporous shell (HCMS) structures were used as a support material for Pt(50)-Ru(50) catalyst, and the catalytic performance of the HCMS supported catalyst in the direct methanol fuel cell was described; the HCMS carbon supported catalysts exhibited much higher specific activity for methanol oxidation than the commonly used E-TEK catalyst by about 80%, provi...

A novel imido-modified SiO2-supported Ti/Mg Ziegler-Natta catalyst for ethylene and ethylene/1-hexene polymerization is investigated. The catalyst is prepared by modification of (SiO2/MgO/MgCl2)TiClx Ziegler-Natta catalysts via supporting vanadium species followed by reaction with p-tolyl isocyanate as imido agents, to get the merits from both the SiO2-supported imido vanadium catalyst and the ...