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

Electrochemical CO 2 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 CO 2 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.