查看更多>>摘要：The strategy of modulating polarization rotation of potassium sodium-niobate ((K_(0.5)Na_(0.5))NbO3, KNN) lead-tree piezoelectric materials was reported to boost piezoelectric properties and resultant piezocatalytic activities. The effectiveness of modulating polarization rotation was proved by degrading Rhodamine B (RhB) using three KNN-based samples with different phase structures (i.e., orthorhombic (O) phase, orthorhombic-tetragonal (O-T) coexistence phase, and rhombohedral-orthorhombic-tetragonal (R-O-T) coexistence phase). Poled samples with the R-O-T coexistence phase show a reaction rate constant of 0.091 min~(-1) owing to the easiest polarization rotation, 2.12 times more than that of poled O-phase featured samples with the most difficult polarization rotation. Enhanced piezocatalytic activities primarily originate from the easier polarization rotation and improved carrier concentration, accompanied by the trace of the mechano-charge generation. Therefore, modulating polarization rotation effectively boosts piezocatalysis of KNN-based materials, promising for harnessing natural energy and disease treatment.
查看更多>>摘要：The creation of high-performing, robust bifunctional electrocatalysts for both cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) in water-splitting is crucial for producing emerging hydrogen economy. Here we report a high entropy alloy (HEA) - FeCoNiCuPd - thin film catalyst, which demonstrated excellent alkaline HER and OER performance with ultralow overpotentials as low as 29 mV for HER and 194 mV for OER at a current density of 10 mA cm~(-2). The outstanding catalytic activity for HER was found to originate from the multiple active sites present on the FeCoNiCuPd surface, while for OER it came from the highly functional (FeCoNi)-oxyhydroxide species formed on the film surface. Moreover, the two-electrode electrolyzer made of the FeCoNiCuPd film electrodes required a low cell voltage of 1.52 V to achieve 10 mA cm~(-2) in 1.0 M KOH, greatly outperforming commercially available Pt/C| |RuO2 electrodes, while maintaining a notable durability. This work demonstrated the remarkable potential of a HEA thin film in catalyzing water-splitting process.
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