High Selective Direct Synthesis of H2O2 over Pd1@γ-Al2O3 Single-Atom Catalyst

Pd-based catalysts are essential for direct synthesis of H2O2 from H-2 and O-2, which still need further improvement of the activity and selectivity by engineering the status of Pd active species. In this work, isolated Pd atoms anchored on Al vacancy of the gamma-Al2O3(100) surface (Pd-1@gamma-Al2O3(100)) are proposed to act as a heterogeneous catalyst for direct synthesis of H2O2 from first-principles theoretical study and micro-kinetic analysis. The thermodynamic stability and whole catalytic mechanism for conversion of O-2 to H2O2 on Pd-1@gamma-Al2O3(100) was studied. It is found that the high selectivity toward H2O2 of Pd-1@gamma-Al2O3(100) is attributed to the high oxidation state of isolated Pd active sites with high stability against atom-aggregation, derived from the strong electronic metal-support interaction. The formation of 3+ cation state of isolated Pd atoms activates adsorbed oxygen molecule for hydrogenation and simnutaously restrains the formation of intermediate toward by-product, compared with traditional bulk Pd catalyst in the metallic state. This work provides theoretical insights into the feasibility of atom-level dispersion Pd to catalyze direct synthesis of H2O2 and guidance for its future development.

Automated summary

In this study, isolated Pd atoms anchored on the Al vacancy of the γ-Al2O3(100) surface (Pd-1@γ-Al2O3(100)) were proposed as a potential heterogeneous catalyst for direct synthesis of H2O2. The Pd-1@γ-Al2O3(100) catalyst exhibited high selectivity and stability, which has promising applications.