Low temperature crystallization of yttrium orthoferrite by organic acid-assisted sol–gel synthesis

• We synthesized yttrium orthoferrite (YFeO3) powder at 450 °C.
• Organic acids influence the crystallization of YFeO3.
• Citric acid increases the purity of yttrium orthoferrite.
• Citric acid reduces the crystallization temperature of YFeO3 down to 450 °C.

Yttrium orthoferrite (YFeO3) is a promising material for visible light photocatalytic applications due to its band gap of 2.2–2.6 eV. However, during the synthesis of YFeO3, unwanted composition can be obtained and the crystallization requires temperatures as high as 850 °C. Powders of YFeO3 were prepared using a sol–gel method with and without organic acids (citric acid, tartaric acid, malonic acid and oxalic acid) used as organic modifiers. The band gap of these powders was measured by diffuse reflection spectroscopy, and the crystallinity and crystalline phase content were characterized by X-ray diffraction. Organic acids allow a higher purity and facilitate crystallization. This work aims to produce YFeO3 powders at the lowest possible temperature. Citric acid was found to be the best additive: it reduces the crystallization temperature below 450 °C. This opens new perspectives such as the deposition of crystalline YFeO3 thin films onto conductive glass for water-splitting applications.