Potential‐Driven Dynamic Spring‐Effect of Pd─Cu Dual‐Atoms Empowered Stability and Activity for Electrocatalytic Reduction

Abstract Atomic‐level catalysts are extensively applied in heterogeneous catalysis fields. However, it is a general but ineluctable issue that active metal atoms may migrate, aggregate, deactivate, or leach during reaction processes, suppressing their catalytic performances. Designing superior intrinsic‐structural stability of atomic‐level catalysts with high activity and revealing their dynamic structure evolution is vital for their wide applications in complex reactions or harsh conditions. Herein, high‐stable Pd─Cu dual‐atom catalysts with PdN 3 ─CuN 3 coordination structure are engineered via strong chelation of Cu 2+ ‐ions with electron pairs from palladium‐source, achieving the highest turnover frequency under the lowest overpotential for Cr(VI) electrocatalytic reduction detection in strong‐acid electrolytes. In situ X‐ray absorption fine structure spectra reveal dynamic “spring‐effect” of Cu─Pd and Cu─N bonds that are reversibly stretched with potential changes and can be recovered at 0.6 V for regeneration. The modulated electron‐orbit coupling effect of Pd─Cu pairs prevents Cu‐atoms from aggregating as metallic nanoparticles. Pd─Cu dual‐atoms interact with two O atoms of H 2 CrO 4 , forming stable bridge configurations and transferring electrons to promote Cr─O bond dissociation, which prominently decreases reaction energy barriers. This work provides a feasible route to boost the stability and robustness of metal single‐atoms that are easily affected by reaction conditions for sustainable catalytic applications.