Synthesis of novel Gr/KTaO3 nanocubes by in-situ grown graphene with improved visible light photocatalytic activity

In this work, a novel method was used to prepare KTaO 3 using KF and Ta 2 O 5 to prepare KTaO 3 nanocubes. Then graphene/ KTaO 3 (Gr/KTaO 3 ) composites were synthesized by in-situ growth of graphene on KTaO 3 nanocubes for the first time. The prepared KTaO 3 possesses a small crystallite size and high crystallinity. The Gr/KTaO 3 composites have higher photocatalytic efficiency compared to pure KTaO 3 . Particularly, Gr/KTaO 3 90 had the highest photocatalytic activity, as it was able to degrade 99.5% of rhodamine B (RhB) within 40 min. According to ultraviolet and visible spectrum (UV-Vis) spectra, the absorption sideband of composites redshifts to the visible light area. Based on the results of PL and EIS, the increasing photocatalytic efficiency can be credited to the fact that graphene provides an efficient channel for electron transfer , which promotes photogenerated electron-hole pairs separation. Moreover, a free-radical trapping test indicated that h + and •OH were the main species in the photodegradation. Our investigation results can serve as a valuable guideline for the development of efficient photocatalysts based on KTaO 3 and graphene, which can be used in the removal of organic pollutants during environmental cleanup.