Combustion method combined with sonochemical step for synthesis of maghemite-supported catalysts for the hydrogenation of 2,4-dinitrotoluene

Maghemite particles were synthesized by using a combined combustion method and sonochemical step. Maghemite was used as carrier to prepare supported Pt and Pd catalysts after deposition via a sonochemical step. The catalysts were immediately ready to be used (metals were catalytically active) for the 2,4-dinitrotoluene hydrogenation to produce 2,4-toluenediamine. The most active catalysts were the Pd/maghemite and bimetallic Pd-Pt/maghemite. The catalysts were easily separable after reaction due to their magnetic properties. • Application of maghemite catalyst supports. • Simplified, efficient and fast sonochemical catalyst preparation method. • Magnetic separable palladium catalysts. • High catalytic activity in hydrogenation of dinitrotoluene.