Defective CeO ₂ /Copper Phthalocyanine S‐Scheme Heterojunctions With Molecular Copper Centers for Selective CO ₂ ‐To‐CO Photoconversion

ABSTRACT Simultaneously regulating charge carrier dynamics and catalytic selectivity remains a critical challenge in photocatalytic CO 2 reduction. Here, we report a copper (II) phthalocyanine/oxygen‐vacancy‐rich (CuPc/CeO 2 ) S‐scheme heterojunction featuring atomically dispersed Cu–N 4 sites. Ultraviolet photoelectron spectroscopy establishes a 0.24 eV work function difference between CeO 2 and CuPc, generating a built‐in electric field that drives S‐scheme charge transfer. X‐ray photoelectron spectroscopy confirms oxygen vacancies in CeO 2 (evidenced by Ce 3+ states), enabling the energetic alignment that spatially separates reductive electrons (−1.05 V vs. NHE) at molecular Cu sites from oxidative holes (+2.44 V) in CeO 2 . Time‐resolved photoluminescence spectroscopy confirmed that the reduction in carrier lifetime (from 7.42 to 6.57 ns) corroborates an efficient charge separation process. In situ diffuse reflectance infrared Fourier‐transform spectroscopy demonstrates that the Cu–N 4 centers preferentially stabilize the *COOH intermediate while facilitating rapid CO desorption from Cu(I) sites, thereby directing selective two‐electron reduction and suppressing over‐reduction to CH 4 . The optimized 20CuPc/CeO 2 catalyst achieves a CO generation rate of 90.23 μmol g −1 h −1 —representing a 16.96‐fold enhancement over pristine CeO 2 —with 92.2% selectivity for CO versus CH 4 , and maintains robust stability over five consecutive photocatalytic cycles. This work establishes a unified design strategy integrating defect‐engineered S‐scheme charge separation with single‐atom molecular catalysis to achieve selective solar‐driven CO 2 ‐to‐CO conversion.