Spontaneous polarisation of ferroelectric BaTiO3/ZnO heterostructures with enhanced performance in a Fenton-like catalytic reaction

Ferroelectric BaTiO3/ZnO heterojunction catalysts synthesised via the sol-gel method present obvious enhancements in spontaneous polarisation-driven Fenton-like catalytic activity. In this study, the oxidative decomposition of methylene blue (MB) dye was used as a model reaction. Pure BaTiO3-activated potassium monopersulphate (PMS) could decompose up to 48% of MB dye in an aqueous solution after 40 min. MB degradation rate firstly increased and then decreased as the ZnO content of the ferroelectric BaTiO3/ZnO heterojunction materials was increased. The maximum degradation rate of 100% and good cycling stability were observed when the BaTiO3:ZnO molar ratio was 1:1. Three active species, namely, holes (h(+)), sulphate radicals (SO4 center dot-) and hydroxyl radicals (OH center dot), were produced following the spontaneous polarisation-driven catalytic degradation of the dye. Amongst these species, h(+) and SO4 center dot- were the main active species. Enhancements in the Fenton-like catalytic activity of BaTiO3/ZnO may be attributed to the formation of semiconductor heterojunctions, which could improve the spontaneous polarisation strength of ferroelectric BaTiO3, promote the effective separation of e(-)-h(+) pairs and accelerate PMS activation. In summary, a novel PMS activation method was developed to provide a nontoxic, efficient and environmentally friendly technology for the degradation of organic pollutants.

Automated summary

Ferroelectric BaTiO3/ZnO heterojunction catalysts synthesized via the sol-gel method show enhanced Fenton-like catalytic activity, with the optimal BaTiO3:ZnO molar ratio of 1:1 for the degradation of methylene blue dye. The enhancements can be attributed to the formation of semiconductor heterojunctions, improving spontaneous polarization strength and accelerating PMS activation for the degradation of organic pollutants.