Naphtha reforming Pt-Re-Ge/γ-Al2O3 catalysts prepared by catalytic reduction: Influence of the pH of the Ge addition step

Pt-Re-Ge/γAl2O3 catalysts were prepared by the catalytic reduction method using different impregnation media (H2O, HCl and NH3) and different Ge contents (0.0, 0.1, 0.3, 1.0 and 2.0%). The influence of these preparation parameters on the activity for n-heptane conversion and the selectivity to toluene at atmospheric pressure was assessed. The catalysts were also characterized by ICP-AES, temperature programmed reduction, pyridine temperature programmed desorption and CO pulse chemisorption. The results show that as the pH is increased the Ge content increases and the catalysts present a lower hydrogenolytic activity and a lower toluene selectivity. Ge addition modifies both metal and acid functions. The catalyst with minimum Ge content prepared using water as impregnation medium has the best performance.