A facile one-pot, three component reaction has been developed using aldehydes, nitroalkane and sodium azide with zinc oxide nanocatalyst for the synthesis of 4-aryl-NH-1,2,3-triazoles. ZnO nanoparticles with controlled size (15-25 nm) and morphology were prepared using a sonochemical strategy. Structural and morphological study revealed the growth of well crystalline particles along the c axis i.e. [0001] direction due to higher surface energy. The catalysis protocol used in this work offers an efficient and highly economical alternative to the existing methods since the reactions proceed smoothly in green solvent polyethyleneglycol (PEG) 400 under aerobic condition. The reaction has a broad substrate scope resulting in excellent yields of the desired products. The catalyst recovery part was tricky at the initial stages; however an alternative route was successfully introduced to recover the former and reused it for the next cycles of catalytic reaction with excellent retentivity in the catalytic activity. The observed high catalytic efficacy with no significant activity loss using recovered catalyst is mainly due to the retention of morphology and crystal structure of ZnO nanoparticles after many catalytic reactions. [GRAPHICS] .