Synthesis of a novel visible light-driven and magnetically separable photocatalyst based on a BiFeO3–YFeO3 type II heterojunction

Abstract

Nanocomposites based on the BiFeO₃–YFeO₃ system with different phase ratios have been synthesized via the solution combustion route. The nominal compositions were set as xBiFeO₃–(1 − x)YFeO₃ (where x = 0.1, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.9), labeled from BYFO-01 to BYFO-09. Glycine was used as a reducing agent for the combustion reaction. The average crystallite size of the obtained materials was in the range of 25–90 nm. A study of the magnetic characteristics and photocatalytic activity of the samples showed that variations in their phase composition significantly enhance both the total magnetization and the photodegradation of rhodamine B dye. All samples exhibit magnetic ordering at room temperature and increased magnetization compared to pure bismuth and yttrium orthoferrites. It was found that the BYFO-04 nanocomposite possesses enhanced photocatalytic activity, which was attributed to the approximately 1 : 1 orthoferrite phase ratio. The BYFO-0.5 and BYFO-0.7 nanocomposites showed an improved magnetic response, with specific and saturation magnetization values of approximately 8 emu g⁻¹ at a field of 4 kOe. The increased magnetization of these samples was explained by their phase composition, which can be technologically controlled. The discovered properties of the synthesized materials are promising for the effective separation of photocatalysts from the reaction medium. The BYFO-0.4 sample photodegraded about 40% of the rhodamine B dye and 80% of methyl violet within 180 minutes of irradiation with visible light. The easy synthesis method, combined with the magnetic and photocatalytic responses and environmentally benign iron sources, makes BiFeO₃–YFeO₃ nanocomposites promising materials for photocatalytic systems and memory recording applications.