Transparent ferroelectric glass–ceramics for wastewater treatment by piezocatalysis

In piezocatalysis the polarization field found in piezoelectric materials enables and enhances catalytic redox reactions. Here, we explore piezocatalytic dye degradation through transparent glass–ceramics containing piezoelectric crystals. 30SiO2–35Li2O–35Nb2O5 (in mol%) glass–ceramics containing varying amounts of LiNbO3 crystallites were fabricated by melt-quenching, followed by heat-treatment at a crystallization temperature of 650 °C for 2, 3 and 6 hours. During piezocatalysis, the 2 hour heat-treated sample showed up to 90% degradation of methylene blue dye within 150 min of ultrasonication, with no significant change in performance after three piezocatalysis cycles. This sample showed promising activity for degrading cationic and neutral dyes, and is optically transparent. This work demonstrates that transparent ferroelectric glass–ceramics are promising for water-cleaning applications by piezocatalysis.