Making pyrocatalytic oxidation of micropollutants real – Revealing the activity-enhancing effects of low-temperature annealing on BaTiO3

Abstract

Among the numerous techniques for water remediation, disinfection, and hydrogen generation, only pyrocatalysis has the potential to harvest and utilize energy from the environment as well as industrial processes in the form of temperature differences. In this work, our purpose was to reach a drastic improvement of the pyrocatalytic activity of BaTiO3 powders (BT) by decreasing the particle size in combination with catalyst annealing at temperatures between RT and 1000 °C. In the end, we reached our goal for a BT with a nominal particle diameter of 50 nm via low-temperature annealing at temperatures of only 300 °C. The activity boost was demonstrated for the dichlorofluorescein (DCF) oxidation assay (+585 %), the degradation of 4-hexylresorcinol (+1150 %) and, for the first time, the successful degradation of the micropollutant bisphenol A (+460 %). Using material characterization in combination with in-depth literature comparisons, we elucidated the underlying mechanism. It deviates strongly from our original assumptions as it includes the generation of oxygen vacancies. Based on our findings, several strategies for further improving pyrocatalysis were derived to enable an effective catalyst design. This will help pyrocatalysis to take the next step on its way towards an energy-efficient technique for water remediation.