High-Throughput Electron Transfer in Inorganic–Organic Interfacial Electric Field Enabling Selective CO2 Photoreduction

The efficiency of photocatalytic CO₂ reduction has long been limited by the competing H₂ evolution reaction. In this study, we present an innovative strategy for boosting high-throughput electron transfer to suppress H₂ evolution, thereby enhancing CO₂ reduction. By employing CdS and cobalt bipyridine as a model, we engineered the surface of CdS to create an electric field at the inorganic–organic interface. Through in situ and transient spectroscopy techniques, we discovered that CdS functionalized with ─COOH groups demonstrates remarkable noncovalent interactions and improved charge transfer capabilities compared to those functionalized with ─NH₂ groups. The fast delivery of electrons on cobalt bipyridine facilitates the adsorbed CO₂ to participate in the proton-electron coupling reaction, rather than allowing adsorbed protons to accept electrons directly. Consequently, the established CdS-COOH/Co(II)-bpy system achieved a CO production rate of 2.523 mmol g⁻¹ h⁻¹ with a selectivity of 96.3%. This research presents an approach for creating efficient charge transport interfaces and provides a comprehensive strategy for designing high-performance photocatalytic CO₂ reduction systems that effectively counteract the challenges posed by competing H₂ evolution reactions.