MORE ACTIVE AND SULFUR RESISTANT BIMETALLIC Pd-Ni CATALYSTS

C. BETTI; N. CARRARA; J.M. BADANO; C. LEDERHOS; C. VERA; M. QUIROGA

QUíMICA NOVA

SOC BRASILEIRA QUIMICA

Lugar: San Pablo; Año: 2018 vol. 41 p. 151 - 156

0100-4042

Theinfluence of the kind of metal precursor and the sequence of impregnation onthe properties of Pd-Ni catalysts was evaluated during the test reaction ofselective hydrogenation of styrene to ethylbenzene by means of physicochemicalcharacterization. The focus was put on the final hydrogenating activity and theresistance to deactivation by sulfided compounds (thiophene).  The used techniques of characterization wereICP, XPS, XDR, TPR, CO chemisorption and TEM. XPS results indicated thepresence of different Pd species: Pdδ-, Pd0 and Pdδ+.  In the case of the Ni containing catalysts,Ni0 and NiO species were also detected.  These palladium and nickel species would beresponsables of the variation of activity and sulfurresistance of the catalysts. NiClPd catalysts had a higher resistanceto deactivation by sulfur poisoning. This was associated to a higher concentration of Pdh+ClxOy species that would prevent theadsorption of thiophene by both steric and electronic effects.  It could also be due to the lowerconcentration of Pd0 and Ni0 on these catalysts, ascompared to those shown by the PdNiCl catalysts.  Both the Pd0 and Ni0species are more prone to poisoning because of their higher electronicavailability.