The effect of Au cocatalyst loaded on La-doped NaTaO3 on photocatalytic water splitting and O2 photoreduction
Abstract Photocatalytic water splitting over La-doped NaTaO 3 (NaTaO 3 :La) was improved by loading with Au cocatalyst which works as H 2 evolution sites. NaTaO 3 :La loaded with Au by an impregnation method showed higher and more steady activity for water splitting than that by a photodeposition method. This difference in the activity for water splitting was related to the O 2 photoreduction on the loaded Au cocatalyst, which is one of the backward reactions of water splitting. The impregnated spherical Au cocatalyst suppressed the O 2 photoreduction by photogenerated electrons more efficiently than the photodeposited hemispherical Au cocatalyst, because the perimeter of Au/NaTaO 3 :La interface which produces activated O 2 molecules was smaller in the impregnated Au than the photodeposited Au.