High-entropy doping and defect co-engineering to synergistically boost piezo-catalytic activity of BaTiO3-based materials

Recently, piezo-catalytic technology with low cost, simplicity and feasibility are drawing more attention in the field of water pollution remediation; nevertheless, the catalytic activity of diverse piezoelectric materials is limited by the rapid recombination of electron-hole pairs and low carrier mobility. Herein, a collaborative strategy of entropy and defect engineerings is proposed to enhance the piezo-catalytic activity of BaTiO3-based materials ((1-x)BaTiO3-xSm(Ca0.2Zn0.2Zr0.2Sn0.2Hf0.2)O3). As x increases, the configuration entropy of the materials is greatly increased from 0 R to 1.3227 R, suggesting that the ceramics with x = 0.05, 0.10, 0.15 and 0.20 possess significantly increased disordering and the ferroelectric long-range order is broken, rendering the materials rich in catalytically active sites and thus enhancing the catalytic performance. In addition, the doping of multiple ions with different ionic radii and valence states leads to abundant oxygen vacancies inside the material, thereby enabling easier separation and migration of electron-hole pairs and resulting in enhanced catalytic activity. Accordingly, the high-configuration-entropy 0.90BaTiO3-0.10Sm(Ca0.2Zn0.2Zr0.2Sn0.2Hf0.2)O3 material with abundant oxygen vacancies exhibits outstanding piezo-catalytic activity, giving the reaction rate constant k of 38.7 × 10−3 min−1 for rhodamine B (RhB). Simultaneously, the 0.90BaTiO3-0.10Sm(Ca0.2Zn0.2Zr0.2Sn0.2Hf0.2)O3 material also show favorable catalytic activity for methylene blue (MB) and methyl orange (MO) with reaction rate constants k of 31.8 × 10−3 min−1 and 19.4 × 10−3 min−1, respectively. This work proposes a novel strategy for enhancing the piezo-catalytic activities of BaTiO3-based piezoelectric materials by the co-engineering of high-entropy doping and defect.