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High-performance piezoelectric materials are critical components for electromechanical sensors and actuators. For more than 60 years, the main strategy for obtaining large piezoelectric response has been to construct multiphase boundaries, where nanoscale domains with local structural and polar heterogeneity are formed, by tuning complex chemical compositions. We used a different strategy to emulate such local heterogeneity by forming nanopillar regions in perovskite oxide thin films. We obtained a giant effective piezoelectric coefficient d 33 , f * of ~1098 picometers per volt with a high Curie temperature of ~450°C. Our lead-free composition of sodium-deficient sodium niobate contains only three elements (Na, Nb, and O). The formation of local heterogeneity with nanopillars in the perovskite structure could be the basis for a general approach to designing and optimizing various functional materials. 

Titanium metal–organic frameworks (Ti‐MOFs), as an appealing type of artificial photocatalyst, have shown great potential in the field of solar energy conversion due to their well‐studied photoredox activity (similar to TiO₂) and good optical responsiveness of linkers, which serve as the antenna to absorb visible‐light. Although much effort has been dedicated to developing Ti‐MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, we have implemented a covalent‐integration strategy to construct a series of multivariate Ti‐MOF/COF hybrid materials PdTCPP⊂PCN‐415(NH₂)/TpPa (composites 1, 2, and 3), featuring excellent visible‐light utilization, a suitable band gap, and high surface area for photocatalytic H₂production. Notably, the resulting composites demonstrated remarkably enhanced visible‐light‐driven photocatalytic H₂evolution performance, especially for the composite 2 with a maximum H₂evolution rate of 13.98 mmol g⁻¹ h⁻¹(turnover frequency (TOF)=227 h⁻¹), which is much higher than that of PdTCPP⊂PCN‐415(NH₂) (0.21 mmol g⁻¹ h⁻¹) and TpPa (6.51 mmol g⁻¹ h⁻¹). Our work thereby suggests a new approach to highly efficient photocatalysts for H₂evolution and beyond.

 

Titanium metal–organic frameworks (Ti‐MOFs), as an appealing type of artificial photocatalyst, have shown great potential in the field of solar energy conversion due to their well‐studied photoredox activity (similar to TiO₂) and good optical responsiveness of linkers, which serve as the antenna to absorb visible‐light. Although much effort has been dedicated to developing Ti‐MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, we have implemented a covalent‐integration strategy to construct a series of multivariate Ti‐MOF/COF hybrid materials PdTCPP⊂PCN‐415(NH₂)/TpPa (composites 1, 2, and 3), featuring excellent visible‐light utilization, a suitable band gap, and high surface area for photocatalytic H₂production. Notably, the resulting composites demonstrated remarkably enhanced visible‐light‐driven photocatalytic H₂evolution performance, especially for the composite 2 with a maximum H₂evolution rate of 13.98 mmol g⁻¹ h⁻¹(turnover frequency (TOF)=227 h⁻¹), which is much higher than that of PdTCPP⊂PCN‐415(NH₂) (0.21 mmol g⁻¹ h⁻¹) and TpPa (6.51 mmol g⁻¹ h⁻¹). Our work thereby suggests a new approach to highly efficient photocatalysts for H₂evolution and beyond.