Gradient p‐p Orbital Hybridization in Bismuth‐Doped Crystalline Carbon Nitride for Dual‐Functional Carbon‐to‐Carbon Valorization

ABSTRACT The deployment of photocatalytic CO 2 reduction is hindered by sluggish multi‐electron kinetics and reliance on kinetically trivial half‐reactions. Achieving thermodynamically balanced “carbon‐to‐carbon” valorization—transforming both CO 2 and organic substrates into value‐added chemical feedstocks—remains a formidable challenge. Herein, we report a bismuth‐doped crystalline carbon nitride (0.075Bi) photocatalyst tailored for the highly efficient, dual‐functional coupling of CO 2 reduction and furfuryl alcohol oxidation. By finely tuning the oxophilic Bi dopant within the heptazine cavities, we establish a unique gradient p‐p orbital hybridization network. Density functional theory (DFT) calculations confirm this hybridization, revealing that Bi 6 p orbitals spatially overlap with the host C 2 p and N 2 p orbitals at the conduction band minimum. This architecture creates an accelerated charge transfer highway and an intensified internal electric field, resolving severe bulk recombination without introducing deep trap states. Under simulated solar irradiation, 0.075Bi successfully manages the stringent thermodynamic requirements to reduce CO 2 into valuable oxygenates, achieving 1.6‐fold and 3.6‐fold enhancements in CO and HCHO evolution compared to pristine carbon nitride. Simultaneously, a steady hole flux drives the stoichiometric oxidation of furfuryl alcohol to furfural, delivering exceptional stability and > 99% product selectivity over a 30‐h reaction. As such, this work provides mechanistic insights into heteroatom‐modulated charge dynamics, establishing a highly stable blueprint for executing synergistic photosynthesis.