Interatomic Spacing‐Dependent Electrocatalytic CO ₂ Reduction: Inert Te Heteroatom Modulation in Hexagonal Pd Nanoplates

Abstract

ABSTRACT Metallic interatomic spacing emerges as a key activity descriptor in electrocatalysis, yet achieving angstrom‐level precision in its dynamic modulation and establishing definitive structure–activity correlations persist as critical bottlenecks. Here, we developed a phase‐controlled strategy enabling continuous interatomic spacing modulation in a library of hexagonal Pd‐Te nanoplates (NPs), where various atomically ordered intermetallic phases from cubic Pd 4 Te to rhombohedral Pd 20 Te 7 /Pd 8 Te 3 and hexagonal PdTe 2 were synthesized, realizing precise tuning of adjacent Pd‐Pd distances (d Pd‐a‐Pd ) from 2.75 to 4.07 Å. The proof‐of‐concept electrochemical CO 2 reduction (ECR) for CO formation displayed a volcano‐shaped dependence on d Pd‐a‐Pd , where Pd 20 Te 7 NPs with a d Pd‐a‐Pd of 2.88 Å exhibited a maximal CO Faraday efficiency (FE CO ) of 99.9%, and preserved FE CO over 90% at ∼120 mA cm −2 during long‐term stability. Integrated in situ spectra and theoretical calculations confirmed the dominated distance effect over electronic effect, and revealed that increasing d Pd‐a‐Pd upshifted d ‐band center toward the Fermi level while altering *CO adsorption configuration from strongly bound *CO T to weakly bound *CO L , resulting in exceptional ECR activity and CO anti‐poisoning capacity on Pd 20 Te 7 NPs owing to the optimally balanced *COOH adsorption and *CO desorption. This study underscores the pivotal role of interatomic spacing in regulating intermediate adsorption configurations for electrocatalysis.