Bi3TaO7 film: a promising photoelectrode for photoelectrochemical water splitting

Abstract

Most of the transition metal bismuth salts have excellent visible absorption range and carrier transport properties due to their unique structure capable of orbits and s–p bonds. As one of the transition metal bismuth salts, Bi₃TaO₇ is firstly directly prepared on fluorine-doped SnO₂ transparent conductive glass (FTO) as a photoanode for photoelectrochemical (PEC) water oxidation via a simple hydrothermal method using a special precursor solution. The growth mechanism of the Bi₃TaO₇ film is investigated in detail. Besides, the Bi₃TaO₇ photoanode exhibits a wide visible light response range with an optical band gap of 2.88 eV, which is useful for its PEC properties. Bi₃TaO₇ achieves an excellent PEC performance by tuning the calcination temperature, producing a photocurrent density of 23.0 μA cm⁻² at 1.23 V vs. RHE and showing excellent stability that decays by only 2% after illumination for 6000 s. The above results indicate that Bi₃TaO₇ has broad application prospects in the field of PEC water oxidation.