Enhanced piezo-catalytic performance of BaTiO3 nanorods combining highly exposed active crystalline facets and superior deformation capability: Water purification and activation mechanism

Using piezoelectric materials for advanced oxidation is a green and viable means of water purification and environmental restoration. However, unmodified piezoelectric catalysts exhibited unsatisfactory catalytic performance, which had become a bottleneck for the practical application of piezoelectric catalysis. In this work, piezoelectric responsiveness and exposed active crystal surface area were rationally coordinated by synthesizing one-dimensional BaTiO3 nanorods (BTO NRs). Enhanced piezo-responsivity enables faster free charge carriers transfer, while the highly exposed area of the (0 0 1) facets provides more active sites for piezo-catalytic reactions. Consequently, BTO NRs degraded RHB (Rhodamine B) and TC (Tetracycline) with first-order rate constants of 0.018 min−1 and 0.012 min−1, respectively, 5 times higher than BaTiO3 nanoparticles. The specific active sites on the (0 0 1) crystal plane were further investigated through a combination of DFT calculations, free radical trapping experiments, and XPS analysis. Ti4+ adsorbs and activates water molecules to generate Ti3+ and •OH, in the catalytic reaction. Afterward, Ti3+ is oxidized to Ti4+ by piezo-holes (holes driven by piezoelectric potential), while •OH is desorbed and involved in the degradation of pollutants. This research not only provides an approach to modify piezoelectric catalysts with high catalytic activity but also presents new insights into the mechanism of piezoelectric catalysis from the viewpoint of the atom level.