Visible-light photo-activity of alkali metal doped ZnO

• We have synthesized Li-, Na- and K-doped ZnO powders by sol–gel process.
• The synthesized samples were characterized by different techniques.
• The photocatalytic activity of materials was evaluated for the degradation of pNP.
• Our synthesized materials exhibit good photocatalytic activity.

In order to utilize visible light more efficiently in the field of photocatalysis, Li, Na and K-doped ZnO nanoparticles were prepared using a sol–gel method. The obtained samples were characterized by BET surface area measurements, X-ray diffraction, scanning electron microscopy and UV–vis analysis.The photocatalytic activity of the photocatalysts was evaluated for the degradation of p-nitrophenol (p-NP) under visible light irradiation. It has been observed that these photocatalysts could be a promising photocatalyst for degradation of organic molecules as compared to transition metal doped ZnO under visible light. Li-doped ZnO is the most active photocatalyst and shows high photocatalytic activity for the degradation of p-nitrophenol (p-NP). The enhanced photocatalytic activity of Li-doped ZnO is mainly due to the electron trapping by lithium metal ions, small particle size, large surface area, and high surface roughness of the photocatalysts.