Competing contributions to the catalytic activity of barium titanate nanoparticles in the decomposition of organic pollutants

There is an increasing demand for innovative solutions to protect the environment from different kinds of industrial pollutants and to complement the existing physical, chemical and biological wastewater treatment techniques. Recently, the use of piezoelectric nanomaterials as catalysts for water purification has been suggested. We show that the observed catalytic activity may not be entirely attributed to the piezoelectric effect of nanomaterials. While piezoelectric-based catalysis has already been studied using several piezoelectric materials, its discrimination against the omnipresent tribocatalysis or sonocatalysis remains in its infancy thus questioning the relevance of the additional piezoelectric contribution. In this study, we investigate the catalytic activities of both piezoelectric barium titanate (BaTiO3) and non-piezoelectric titanium dioxide (TiO2) to distinguish between sono- tribo- and piezocatalytic contributions. Comparing the catalytic performance of BaTiO3 and TiO2 for different concentrations and temperatures gives an approach to better understand the contribution of different physical effects to the catalytic activity of BaTiO3. It is shown that for otherwise identical properties such as size, crystallinity and similar properties of surface terminations, the comparison of TiO2 and BaTiO3 yields a contribution of around 90 % to the piezoelectric effect in the BaTiO3 catalytic response.