Plasmon‐Ferroelectric Induced Multifield Coupling Effect Accelerates Charge Spatial Separation for Boosting Tandem Photoredox Catalysis

Abstract Integrating solar‐driven CO 2 reduction with organic oxidation is regarded as an ideal strategy for achieving carbon neutrality. However, further enhancement of photocatalytic efficiency is persistently blocked by low photogenerated carrier yields and unavoidable fast bulk electron/hole recombination. Herein, we propose to design a plasmonic‐ferroelectric heterojunction (WO 3‐x /K 4 Nb 6 O 17 ), which enhances localized electromagnetic field and ferroelectric polarization field simultaneously through the cooperative coupling of localized surface plasmon resonance (LSPR) effect in WO 3‐x and ferroelectric polarization in K 4 Nb 6 O 17 , thereby not only promoting energetic hot‐carriers generation, but also accelerating bulk charge separation. Ultimately, hot‐electrons and photoelectrons are directionally transferred and extracted to K 4 Nb 6 O 17 surface for CO 2 reduction, whereas massive holes are accumulated in WO 3‐x for benzylicalcohol activation. Under mild conditions, WO 3‐x /K 4 Nb 6 O 17 exhibits superior CO yield (294.76 µmol g −1 h −1 ), which is 9.87 and 6.27‐folds higher than that of K 4 Nb 6 O 17 and WO 3‐x , respectively. Meanwhile, compared to the simple dehydrogenation of benzylicalcohol to benzaldehyde in K 4 Nb 6 O 17 and WO 3‐x , WO 3‐x /K 4 Nb 6 O 17 prefers to trigger benzylicalcohol C─C coupling for directed production of more value‐added hydrobenzoin (313.15 µmol g −1 h −1 ). This work would open a conceptual vista for designing multifield coupling structures to facilitate charge spatial separation and directional transfer, which would inspire further establishment of efficient novel photocatalysts and solar‐to‐fuel conversion systems to meet the green and sustainable development goals.