Complete solid solutions between LaTaON2 and SrZrO3, i.e. (LaTaON2)(1-x)(SrZrO3)(x) (0 <= x <= 1) have been built which are very useful in tailoring many important parameters of LaTaON2. Band gap of LaTaON2 becomes tunable by controlling the level of solid solutions with SrZrO3. Structural distortions, defects (e.g. Ta4+ species) concentration and surface hydrophilicity of LaTaON2 are largely improved by introducing SrZrO3 in the structure. These modifications contribute to much enhanced photocatalytic activities of solid solutions for oxygen production which clearly outperform pristine LaTaON2 under visible light illumination. Apparent quantum efficiency as high as 0.87% at 420 +/- 20 nm was achieved at (LaTaON2)(0.6)(SrZrO3)(0.4)(x = 0.4). Further analysis suggest that introducing SrZrO3 results in realignment of band edge positions of LaTaON2 so as to be more appropriate for water splitting reactions. (C) 2020 Elsevier Inc. All rights reserved.