Facile synthesis, characterization and enhanced catalytic reduction of 4-nitrophenol using NaBH(4) by undoped and Sm(3+), Gd(3+), Hf(3+) doped La(2)O(3) nanoparticles

This work focuses on the synthesis of undoped and doped lanthanum oxide nanoparticles (La(2)O(3) NPs) by a simple co-precipitation method for the catalytic reduction of 4-nitrophenol (4-NP) using NaBH(4) as a reducing agent. Their optical properties, morphologies, structure, chemical compositions and electronic properties were carefully characterized by XRD, FTIR, SEM, TEM, PL and UV–visible absorption spectroscopy. The SEM and TEM images showed various shape morphologies and sizes of the particles. The XRD pattern revealed a polycrystalline nature with the hexagonal structure of the La(2)O(3) NPs. The synthesized undoped and doped La(2)O(3) NPs were also employed as catalysts for the reduction of 4-nitrophenol, it shows that the doped (Sm(3+), Gd(3+) and Hf(3+)) La(2)O(3) NPs provided better catalytic activity than the undoped La(2)O(3) NPs. Moreover, Hf(3+) doped La(2)O(3) NPs exhibited an enhanced catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol in 90 min. The catalytic conversion was studied by UV–vis spectroscopy with high reduction rate (k = 2.048 min(−1)). The applications of the present study may utilize in the removal of toxic pollutants in a cleaning of environmental pollution as well as in industrial applications.