Masked second-shell sulfur coordinating atomically dispersed Pd on tin oxide boosts the direct synthesis of hydrogen peroxide

The coordination environments of isolated metals significantly influence the catalytic properties of materials. However, challenges persist in the precise modulation of these microenvironments. In this study, we achieved atomically dispersed Pd on sulfur-doped tin dioxide (SnO 2 ) through the controlled oxidation of SnS 2 nanosheets pre-loaded with single-atom Pd (Pd/SnS 2 ). Our findings reveal that the synthesized catalyst features a central single-atom Pd, which coordinates with oxygen and tin in the first coordination shell and sulfur binding tin in the second shell. The coordination of isolated Pd with sulfur in the out-of-plane second shell layer enhances oxygen adsorption while inhibiting O O dissociation, thus directing hydrogen peroxide selectivity. This results in a higher productivity and durability of hydrogen peroxide compared to pristine Pd/SnS 2 and traditional samples. This work presents an effective strategy to tailor and preserves the coordination micro-environment of central single-atom metals during catalytic reactions.