This study improved the photocatalytic activity of NaTaO3 by replacing some Na ions in the 12-coordinate sites with larger K ions. Na 1-xKxTaO3 photocatalysts of x = 0-0.2 were synthesized by the sol-gel method. K-doping at x = 0.05 resulted in rectifying the distorted perovskite NaTaO3 to a pseudo-cubic phase as well as significantly promoting the photocatalytic activity. The 180° bond angle of Ta-O-Ta in the pseudo-cubic phase may facilitate the separation of photogenerated charges for effective water splitting. Photoluminescence spectroscopic analysis confirmed that the flattened Ta-O-Ta linkage with K-doping suppresses the recombination of photogenerated charges. Further K-doping (with x > 0.05) leads to impurity formation, which bends the Ta-O-Ta linkage and creates defect states, lowering the photocatalytic activity of the K-doped NaTaO3. This study demonstrates that an appropriate ion replacement to tune the crystal structure can significantly promote electron transport in photocatalysts and thus their activity.
All Science Journal Classification (ASJC) codes
- Materials Chemistry