On the origin of the high performance of MWNT-supported PtPd catalysts for the hydrogenation of aromatics

摘要: Abstract This work reports some surface and structural features of multi-wall carbon nanotubes (MWNT)-supported PtPd crystallites in order to explain their very good ability hydrogenate aromatic rings comparison with other catalyst systems consisting the same metallic function but changing support substrate (amorphous SiO2–Al2O3 (ASA) silica-delaminated zirconium phosphate (ZrPSi)). The bimetallic catalysts were prepared by simultaneous impregnation respective supports metal salt precursors characterized using chemical analysis, nitrogen adsorption–desorption isotherms at 77 K, temperature-programmed desorption-mass spectroscopy (TPD-MS), DRIFT adsorbed NH3 (DRIFT-NH3), X-ray diffraction (XRD), transmission electron microscopy (TEM) photoelectron measurements (XPS). tested vapor-phase hydrogenation (HYD) naphthalene toluene presence dibenzothiophene (DBT; 100 ppm S) 5 MPa total pressure. Irrespectively reactant molecule, PtPd/MWNT showed a higher initial turnover frequency (TOF) than PtPd/ZrPSi PtPd/ASA counterparts. enhancement activity observed was related ensemble effect Pt48Pd25 alloy located on outer MWNT. Upon on-stream conditions lowest thioresistence, sintering coking among studied. improved resistance this is interpreted terms reactivity changes coke induced sulfur as well acidity catalyst.