Hollow Pd-Sn Nanocrystals for Efficient Direct H2O2 Synthesis: The Critical Role of Sn on Structure Evolution and Catalytic Performance

The development of efficient catalysts with high activity and selectivity for the direct synthesis of H2O2 from H-2 and O-2 is highly desirable yet challenging. Herein, a series of Pd-Sn bimetallic nanocrystals with hollow structure have been successfully created as highly active and selective catalysts for direct H2O2 synthesis. We found that the introduction of Sn played an important role on the morphology evolution and composition control of the hollow Pd-Sn nanocrystals. Significantly, after rapid thermal treatment, the obtained hollow Pd-Sn/TiO2 catalysts can deliver complete inhibition of H2O2 decomposition/hydrogenation, resulting in a large activity enhancement for the H2O2 production. The H-2 selectivity could be further improved by using water as the reaction solvent. Further investigation showed that the large activity enhancement of hollow Pd-Sn/TiO2 catalysts for the direct H2O2 synthesis can be attributed to the presence of PdO, the ensemble effect between the Pd and Sn, and the interface effect of Pd/SnOx and PdO/SnOx.