Liberating photocarriers in mesoporous single-crystalline SrTaO2N for efficient solar water splitting

Porous single-crystalline SrTaO 2 N, combining structural homogeneity and high porosity, afford a great promise as an active photocatalyst. The lack of grain boundaries in SrTaO 2 N porous single crystals (PSCs) enables fast photocarrier migration from bulk to the surface whilst the high porosity offers adequate accessible surface to perform photocatalytic reactions. In this work, we demonstrate a facile synthesis of SrTaO 2 N PSCs via a topotactic conversion route. These SrTaO 2 N PSCs deliver exceptional activity and stability for photocatalytic O 2 production from water with a record-breaking apparent quantum efficiency as high as 17.9% at 420 ± 20 nm. Overall water splitting with H 2 /O 2 equals 2 has also been attained in a Z-scheme system employing SrTaO 2 N PSCs as the O 2 -evolution moiety. These results signify a paradigm to improve photocatalytic performance based on PSCs, which extends the toolbox to achieve efficient solar water splitting over conventional photocatalysts.