Heterogeneous photocatalytic degradation of 4-nitrophenol in aqueous suspension by Ln (La3+, Nd3+ or Sm3+) doped ZnO nanoparticles

Lanthanide doped ZnO nanoparticles with different Ln (Ln = La, Nd and Sm) contents were synthesized by polymer pyrolysis method and characterized by various techniques such as XRD, UV–vis, SEM, TGA, and TEM. The XRD results revealed that Ln3+ is uniformly dispersed on ZnO nanoparticles in the form of small Ln2O3 cluster. From SEM and TEM images it was found that the particle size of La-doped ZnO is much smaller as compared to that of pure ZnO. The photocatalytic activity of La-doped ZnO in the degradation of 4-nitrophenol (4-NP) was studied. The effects of the type and amount of loadings on the photocatalytic activity of Ln-doped ZnO were studied and the results were compared with pure ZnO. It was observed that the rate of degradation of 4-NP over Ln-doped ZnO increases with increasing La, Nd and Sm loading up to 4, 4 and 8 wt% and then decreases. It was found that the doping of Ln in ZnO helps to achieve complete mineralization of 4-NP within a short irradiation time. Among the catalysts, the 4 wt% Nd-doped ZnO was the most active and showing high photocatalytic activity for the degradation of 4-NP.

Lanthanide doped ZnO nanoparticles with different Ln (Ln = La, Nd and Sm) contents were synthesized by polymer pyrolysis method. The Ln doping significantly affects the particle size and makes the maximum of the UV absorbance band shifts toward the higher wavelength. Among the catalysts, the 4 wt% Nd-doped ZnO was the most active and showing high photocatalytic activity for the degradation of 4-NP.Figure optionsDownload high-quality image (97 K)Download as PowerPoint slideHighlights
► Ln (La, Nd and Sm) doped nano ZnO were synthesized by polymer pyrolysis method.
► The Ln doping affects the particle size and the UV absorbance of ZnO.
► Degradation of 4-nitrophenol was investigated by using these catalysts.
► 4 wt% Nd/ZnO was the most active and showing high photocatalytic activity.