An exceptionally active and selective Pt–Au/TiO2catalyst for hydrogenation of the nitro group in chloronitrobenzene

Abstract

Adding a very small amount of Pt entities (0.01–0.03 wt%) onto the Au surface of a Au/TiO₂ catalyst is found to be an efficient approach to improve the catalytic activity of Au for the hydrogenation of p-chloronitrobenzene (p-CNB), without loss of selectivity towards p-chloroaniline (p-CAN). The effect of catalyst amount, reaction temperature, H₂ pressure and reaction time on p-CNB hydrogenation was studied with 0.02wt%Pt–0.5wt%Au/TiO₂ (Pt_0.0002–Au_0.005/TiO₂). The selectivity to p-CAN could be up to 100% at complete conversion of p-CNB with reaction temperatures at or below 333 K. The catalyst also exhibited perfect stability. The catalyst structure was characterized by TEM and XRD, and the mechanism of the high activity of the catalyst was discussed.