Efficacité des ultrasons focalisés haute intensité Ulthera® dans la remise en tension de l’ovale du visage

Abstract

Phosphorus (P) modified boehmite catalysts were prepared with wet impregnation method using phosphoric acid (H3PO4) as the P source. The P/boehmite catalysts with different P loadings ranging from 0 to 6.4 wt% were obtained by regulating the concentration of H3PO4. These catalysts were characterized by BET surface area and FTIR spectroscopy measurements and their catalytic performance for hydrogen generation by methanolysis of sodium borohydride at 0 °C was evaluated. The results show that the as-prepared non-metallic P/boehmite catalyst exhibited high catalytic activity toward the methanolysis reaction under the circumstance of low environmental temperature. Appropriate calcination treatment can enhance the catalytic activity of P/boehmite catalyst to some extent. To understand the kinetic behavior of the methanolysis reaction in the presence of these catalysts, the experimental data were fitted to both zero-order and first-order kinetic models using the integral method.