A review of advances in multifunctional XTiO 3 perovskite-type oxides as piezo-photocatalysts for environmental remediation and energy production.

Over more than three decades, the field of engineering of photocatalytic materials with unique properties and enhanced performance has received a huge attention. In this regard, different classes of materials were fabricated and used for different photocatalytic applications. Among these materials, recently multifunctional XTiO ₃ perovskites have drawn outstanding interest towards environmental remediation and energy conversion thanks to their unique structural, optical, physiochemical, electrical and thermal characteristics. XTiO ₃ perovskites are able to initiate different surface catalytic reactions. Under ultrasonic vibration or heating, XTiO ₃ perovskites can induce piezo-catalytic reactions due to the titling of their conduction and valence bands, resulting in the formation of separated charge carriers in the medium. In addition, under light irradiation, XTiO ₃ perovskites are considered as a new class of photocatalysts for environmental and energy related applications. Herein, we addressed the recent advances on variously synthesized, doped and formulated XTiO ₃ perovskite-type oxides showing piezo- and/or photocatalytic exploitation in environmental remediation and energy conversion. The control of structural crystallite size and phase, conductivity, morphology, oxygen vacancy control, doping agents and ratio has a significant role on the photocatalytic and piezocatalytic activities. The different piezo or/and photocatalytic processes mechanistic pathways towards varying applications were discussed. The current challenges facing these materials and future trends were addressed at the end of the review.
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