Exploring the Role of Titanate Perovskites in the Oxidation of Amines via Photocatalysis.

Abstract

Considering that structural differences could affect the photocatalytic efficiency of titanate perovskites, cubic SrTiO₃ (STO) and tetragonal CaTiO₃ (CTO) were synthesised as models to elucidate the structure-activity relationship. STO and CTO materials were produced through hydrothermal approaches, adjusting parameters such as temperature and pressure to optimise material purity. Among the perovskite photocatalysts, two stand out for their exceptional photocatalytic capacity and crystalline purity: CaTiO₃, prepared at 180 °C for 36 h, and SrTiO₃, synthesised at 200 °C for 24 h. Notably, we explore the selective ability of these materials for the photocatalytic oxidative self-coupling of benzylamine (BZA) to produce N-benzylidenebenzylamine (BZI), with CaTiO₃ emerging as the most efficient catalyst for this reaction. The CTO material prepared at 180 °C for 36 h (CTO180T-36) achieved a peak BZI production of 0.5 mM, with a total conversion of BZA after 7 h of irradiation. This study also emphasises the crucial role of reaction conditions and perovskite morphologies in fine-tuning photocatalytic performance. These findings highlight opportunities for developing efficient and selective photocatalytic processes, holding the compromise for applications in organic synthesis and sustainable green chemistry.