Mesoporous single-crystalline SrNbO2N: Expediting charge transportation to advance solar water splitting

Grain boundaries serve as an interception to the transportation of photo-generated charges (e - and h + ), severely undermining the photocatalytic performance. In this work, SrNbO 2 N porous single crystals (PSCs) free of grain boundaries have been synthesized, which deliver exceptionally high photocatalytic activity and stability for water oxidation reactions. The removal of grain boundaries warrants fast charge transportation, reducing the risks of charge recombination. The high porosity of PSCs supplies ample inner surface to carry out catalytic reactions. Deposited with a proper cocatalyst, SrNbO 2 N PSCs can photocatalyze water oxidation into O 2 with apparent quantum efficiency (AQE) as high as 5.64% at 420 ± 20 nm. The high activity is also exemplified by integrating SrNbO 2 N PSCs into a Z-scheme system which can split water into H 2 and O 2 in stoichiometry under simulated solar insolation. These findings not only prove that PSCs expedite charge migration, triggering a high activity for photocatalytic reactions, but also enliven more attention upon traditional materials that hold the potential for solar energy conversions. SrNbO 2 N porous single crystals, combining structural homogeneity and high porosity, expedite photocarrier transportations, which in turn, deliver exceptional high performance for photocatalytic water oxidation into O 2 under visible light illumination. • SrNbO 2 N porous single crystals (PSCs) have been fabricated. • SrNbO 2 N PSCs have superior photocarrier separation conditions. • SrNbO 2 N PSCs deliver exceptional performance for photocatalytic O 2 production. • SrNbO 2 N PSCs achieved AQE as high as 5.64% at 420 ± 20 nm. • Overall water splitting has been realized for SrNbO 2 N PSCs in a Z-Scheme system.