SrTaO2N co-doped with La/Zr as promising photocatalysts for water reduction under visible light illumination

La/Zr co-doped SrTaO2N has been investigated as visible-light-active photocatalysts for water reduction. Unlike previous aliovalent doping that leads to a decrease in light absorption, La/Zr co-doping largely preserves the visible light absorption of SrTaO2N. More importantly, the La/Zr co-doping not only helps to improve surface hydrophilicity and reduce particle sizes but also effectively inhibits defect formation (e.g. Ta4+) in SrTaO2N. These modifications are responsible for significant enhancements in photocatalytic H2 production. AQE as high as 0.84% was achieved at 420 ± 20 nm for Sr0.4La0.6Ta0.4Zr0.6O2N (x = 0.6), which also showed good durability and stability. Further analysis suggests that La/Zr co-doping negatively shifts the conduction band edge positions of SrTaO2N and contributes to better charge separation conditions.