Due to increase in water pollution, there is a need to dwindle this problem for a clean and green future. Photocatalysts like ZnO, CaO and TiO2 have proved to be triumphant in removal of environmental contaminants. In this present work, ZrC nanopowder has been synthesized using a single-step reduction technique by heating zirconium oxide (ZrO2) and hexane (C6H14) in metallic Mg powder and is used as a photocatalyst for the degradation of methylene blue (MB) dye under solar radiation. Optimization of synthesis parameters (temperature, holding time and carbon content) has been done to obtain single phase ZrC. Various characterization techniques like X-ray diffraction (XRD), transmission electron microscope (TEM), differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) and X-ray photoelectron spectroscopy (XPS) were studied for various structural, thermal and surface characteristics of as-synthesized samples. The effect of synthesis parameters on crystal distortion of ZrC particles was studied with the help of Double Voigt analysis. Further, the comparative catalytic activity as photodegradation of MB dye with the help of optimized sample was studied under UV and solar radiations. As an effect of illumination source with the same concentration of catalyst and dye, 80% degradation was observed under solar radiations which is quite higher than that observed under UV in 5 h. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.