Absrtact. Preparation of fine TaON particles is attempted to improve the photocatalytic activity for H2 evolution from aqueous methanol solution under visible light (a > 420 nm). TaON is synthesized by nitriding Ta2O5 powder at 1123 K for 15 h under a flow of NH3. When nanoparticulate Ta2O5 with a primary particle size of 30–50 nm is used as the precursor, fine particles of TaON (FP-TaON)…