Potential-Driven\nCoordinated Oxygen Migration in an\nElectrocatalyst for Sustainable H<sub>2</sub>O<sub>2</sub> Synthesis

Local coordination environment (LCE) manipulation has\nemerged as\na significant approach for modulating the electrocatalytic behavior\nof low-dimensional nanomaterials. However, challenges persist in accurately\nidentifying active sites and understanding dynamic changes during\noperation. Here, we underscore the influence of LCE on the electrochemical\nproduction of H<sub>2</sub>O<sub>2</sub>, utilizing the Pd cluster\nas a model catalyst. Density functional theory (DFT) calculations\nillustrate the role of first- and second-coordinated sulfur and oxygen\nin modulating the binding strength of HOO*. Guided by DFT screening,\nthe as-prepared Pd cluster (Pd<sub><i>x</i></sub>/HMCS)\ncatalyst presents exceptional catalytic performance with a high mass\nactivity of 4.06 A mg<sup>–1</sup> at 0.45 V and selectivity\nabove 94%. The Pd<sub><i>x</i></sub>/HMCS catalyst also\ndelivers promising potential for industrial practices with a production\nrate of 16.3 mol g<sub>cat</sub><sup>–1</sup> h<sup>–1</sup> in flow cell evaluation. Elaborated in situ characterizations confirm\nthat under operation, oxygen migrates from the second coordination\nsphere (CS) to the first CS to achieve oxygen coverage on the catalyst\nsurface. Such an oxygen migration phenomenon and the optimized first\nand second coordination environment give rise to the outstanding performance.