A Self‐Adaptive Quantum Dots/BaTiO ₃ Junction Together with Giant Charge Separation‐Driving Force for CO ₂ Photoreduction via Ferroelectric Polarization Engineering

Abstract Quantum dots (QDs) with multiple exciton generation are identified as one of the most competitive candidates for highly efficient solar‐to‐chemical energy conversion, yet not well recognized in excellent CO ₂ photoreduction activity due to the agglomeration and exciton effect. Here, taking Zn _0.5 Cd _0.5 S QDs (ZCS QDs) as an example, ferroelectric BaTiO ₃ (BTO) with high‐energy state polarization charges is introduced to dynamically tune the properties of interfacial charges, achieving self‐adaptive electrostatic adsorption of QDs and intensive photogenerated charge separation. Meanwhile, in synergy with the Z‐scheme ZCS QDs/BTO heterojunction, carrier recombination is further inhibited. Such a subtle charge modulation exhibits an exceptional improvement in CO ₂ photoreduction, reaching CO yields that are 15.06 times and 2.13 times those of the pure BTO and ZCS QDs, respectively. Notably, there is a remarkable 8.67 times further increase in CO yield for external polarization. The validity of the polarization charges modulating strategy for boosting CO yield is further demonstrated using the double‐layer capacitance ( C _dl ) and in situ Fourier transform infrared spectroscopy. This study shows great promise for ferroelectric materials in CO ₂ photoreduction.