La Doping ATaO₃ (A = Li, Na, K) to Improve Performance for Photocatalytic Pollutant Degradation

ATaO3 (A = Li, Na, K) photocatalysts are among the most efficient photocatalysts, and efficiency can be further improved by La doping. In this study, the effect of La doping on ATaO3 perovskites was explored for several A site elements. ATaO3 (A = Li, Na, K) nanoparticles were synthesized via a solid-state high temperature synthesis with varying La mol % doping (0–10%). Homogeneous La doping within NaTaO3 and KTaO3 bulk was achieved, with an additional single (at times double) atomic layer at the surface of the nanoparticles, as confirmed by scanning transmission electron microscopy. Doping in LiTaO3 was inhomogeneous and requires further development. Formation and surface energy calculations and corresponding Wulff shapes were correlated to these experimental observations, confirming the role of La dopants in the observed shape of these nanoparticles. Model pollutant photocatalytic reactions under flow conditions confirmed an increase in photocatalytic activity with La doping for all ATaO3, with the largest improvement observed for NaTaO3. The findings of this study highlight the effect of La doping in ATaO3 (A = Li, Na, K) perovskites to improve photocatalytic performance for various applications, including energy and pollutant degradation.