Beyond d Orbits: Steering the Selectivity of Electrochemical CO₂ Reduction via Hybridized sp Band of Sulfur‐Incorporated Porous Cd Architectures with Dual Collaborative Sites

Abstract Electrochemical CO₂ reduction is regarded as a promising strategy for the sustainable conversion of greenhouse gas. However, it still remains a significant challenge to manipulate the selectivity and activity. Herein, amorphous and porous Cd modified by sulfur (P–Cd|S) is synthesized by a p‐block sulfur dopant. In comparison with unmodified Cd metal, the P–Cd|S architecture exhibits superior activity for selective CO generation, indicating that the sulfur dopant enables a selectivity shift from formic acid to CO. The high selectivity of P–Cd|S is partially ascribed to the local alkalization and suppression of hydrogen evolution as indicated by the finite element analysis. In‐depth mechanistic investigations by operando Raman, Infrared, and X‐ray photoelectron spectroscopy in combination with theory calculations indicate that the covalently hybridized sp band system with dual collaborative sites (Cd^δ+ and S^δ−) gives rise to a strong interplay with CO₂ molecules and carbonaceous species, leading to the natural elimination of linear correlation among intermediates binding for d‐band metals and the convenient modulation of selectivity toward CO versus HCOOH.