Selective Oxidation of Glycerol over Platinum-Based Catalysts Supported on Carbon Nanotubes

Platinum was supported on multiwalled carbon nanotubes by the traditional incipient wetness impregnation and tested in the selective oxidation of glycerol. This catalyst is prone to deactivation possibly by oxygen poisoning. A platinum catalyst prepared by the sol immobilization technique is less susceptible to deactivation, probably due to the higher average size of the particles obtained; in addition a high and stable selectivity toward glyceric acid was observed throughout the reaction (67%). Tests with a Pt-Au bimetallic catalyst under high pH conditions show that deactivation is suppressed. Moreover, this catalyst is able to enhance the selectivity toward dihydroxyacetone (DIHA) in acid medium, when compared to a monometallic platinum catalyst with the same total metal loading (21% vs 13%), although a poorer performance had been obtained.