Flame Spray Pyrolysis Engineering of Nanosized Mullite-Bi2Fe4O9 and Perovskite-BiFeO3 as Highly Efficient Photocatalysts for O2 Production from H2O Splitting

Bi-Fe oxides are stable materials with potential photocatalytic activity under solar light photons. So far, however the of pure-phase nanosized mullite-Bi2Fe4O9 has not been studied. Usually, synthesis is hampered by co-formation perovskite BiFeO3. Herein we demonstrate that nanoparticles prepared Flame Spray Pyrolysis (FSP) technology highly efficient O2 production photocatalysts, achieving >1500 ?mol g?1h?1. This outperforms all -so far reported- Bi-Fe-O photocatalysts. We present an FSP-based process for a versatile platform, can be easily optimized to obtain 100% or perovskite-BiFeO3 their heterojunctions. The phase-evolution studied XPS, Raman, and EPR spectroscopies. Short post-FSP annealing impacts photoactivity BiFeO3 Bi2Fe4O9 in distinct ways. Fe2+ centers improve dramatically its efficiency, while solid-melt formation limiting factor.