Efficient Direct H₂O₂Synthesis Enabled by PdPb Nanorings via Inhibiting the O-O Bond Cleavage in O₂and H₂O₂

Direct H2O2 synthesis (DHS) from H2 and O2 is a promising process in industry; however, challenges related to poor H2O2 selectivity and low H2O2 yield remain. We report here that PdxPb nanorings (NRs) can serve as high-efficiency catalysts for DHS. We demonstrate that the preferential location of Pb species at the edge and corner can significantly decrease the amount of low-coordinated Pd atoms in PdxPb NRs, leading to an enhanced H2O2 yield and selectivity but a reduced degradation rate. Consequently, the optimized catalyst gives a H2O2 yield of 170.1 mol kgcat-1 h-1, being one of the best catalysts reported for DHS to the best of our knowledge. Theoretical calculations reveal that PdxPb NRs are favorable for OOH formation, a key intermediate for DHS, while Pd NRs tend to dissociate O2 to form H2O in the presence of H2. On the other hand, the cleavage of O-O in H2O2 is strongly suppressed on PdxPb NRs, leading to a low H2O2 degradation rate. This work highlights the significance of catalyst surface modifications, especially the control of Pd coordination environment on DHS performance, which may provide deep insight for catalyst design in heterogeneous catalysis.