A series of single semiconductors and their nanocomposites combination (such as KTaO 3 +CdSe+SrTiO 3 ; KTaO 3 +CdS+WO 3 ; KTaO 3 +CdS+MoS 2 ) were prepared using hydrothermal route. Photocatalytic activity of as-prepared nanocomposites was estimated by photocatalytic degradation of toluene in the gas phase using light-emitting diodes (LEDs, 375nm) in four subsequent cycles. The nanocomposites were characterized by scanning electron microscopy (SEM), X-ray powder diffraction analysis (XRD), UV–vis diffuse-reflectance spectroscopy (DRS) and BET surface area measurements. It was observed that hierarchical 3D structures caused an increase of the photocatalytic activity in gas phase.