A comparative study of palladium-gold and palladium-tin catalysts in the direct synthesis of HO

Herein we evaluate the promotive effect of Au and Sn incorporation into supported Pd nanoparticles for the direct synthesis of H 2 O 2 from molecular H 2 and O 2 . The introduction of both secondary metal modifiers was found to result in a significant enhancement in catalytic performance, although, in the case of the PdSn system, it was identified that relatively large quantities of the secondary metal were required to rival the activity observed over optimal Au-containing formulations, with the 0.25%Pd-2.25%Sn/TiO 2 catalyst offering comparable H 2 O 2 synthesis rates to the optimised 0.25%Pd-0.25%Au/TiO 2 formulation. The introduction of Sn was found to considerably improve Pd dispersion, correlating with an improvement in selective H 2 utilisation. Notably, the optimal PdSn catalyst identified in this work achieves superior H 2 O 2 selectivities compared to the PdAu analogue and is able to rival the performance of state-of-the-art materials. Supported PdSn catalysts are highly effective for the direct synthesis of hydrogen peroxide showing significantly higher selectivity to comparable PdAu catalysts.