Oxide perovskite materials with ABO3 structure have
been widely employed for photocatalytic applications. However, owing
to the disadvantageous electron–hole recombination process
and wide bandgap of some materials, the photocatalytic performance
is seemingly restricted. Coupling two catalysts together through the
formation of a heterojunction ensures effective charge carrier separation.
The intimate interaction between the materials is propitiously useful
for charge transfer, thereby increasing the efficacy. In this study,
the photocatalytic activity of a K
x
Na(1‑x)NbO3–BaBiO3 (KNN-BBO) heterojunction material for the degradation of
Rhodamine 6G organic dye was investigated. The materials were extensively
characterized by X-ray diffraction, UV–Vis diffused reflectance
spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy,
and N2 adsorption isotherms. The degradation efficiency
of the organic contaminant under 1 sun simulated sunlight is monitored
by spectral analysis from UV–Vis absorption spectroscopy. The
resistance to charge transfer was also observed by electrochemical
impedance spectroscopy. The effect of the sintering temperature on
the photoinduced degradation activity was also included in our study.
An unsintered KNN-BBO (UKB) composite material is found to be the
most efficient catalyst with 84% removal efficiency as compared to
the sintered one (SKB). This is attributed to the reduced bandgap
with staggered-type band alignment, increased surface area, and surface
oxygen vacancy states. Together with the crucial findings of this
work, a probable mechanism for enhanced photocatalytic activity has
been proposed here.