New Pd-Pt and Pd-Au catalysts for an efficient synthesis of H2O2 from H2 and O2 under very mild conditions

Bimetallic Pd-Pt and Pd-Au samples supported on sulfated zirconia were successfully tested for the direct synthesis of hydrogen peroxide under very mild conditions (I bar and 293 K) and outside the explosion range. The effect of the addition of Pt to Pd in enhancing the yield of hydrogen peroxide is sensitive to the Pt amount: only using a low Pt content it is possible to improve H2O2 selectivity (from 55% to 70%) and productivity with respect to the monometallic sample. The addition of gold in 1:1 amount to palladium improved both the productivity and even more the selectivity of the process, producing a hydrogen peroxide concentration already useful for industrial applications and maintaining a stable selectivity (62%) after 12 h of time on stream. (C) 2009 Elsevier B.V. All rights reserved.