Fabrication of modified Sb2O3 nanospheres for the removal of hazardous malachite green organic pollutant and selective NO2 gas sensor

Sb₂O₃ and Ni modified Sb₂O₃ (Ni–Sb₂O₃) nanospheres were synthesized using low cost co-precipitation method and characterised using various instrumental methods such as X-ray Powder Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FT-IR) spectroscopy. The XRD pattern reveals cubic crystal lattice. The average size of Sb₂O₃ and Ni–Sb₂O₃ nanoparticles was calculated to be around 41 nm and 29 nm, respectively. The HR-TEM investigation of the Sb₂O₃ nanomaterial reveals homogeneous spherical balls with a fine dispersion. The random-shaped nanoparticles with porous surfaces and voids were revealed by SEM. EDS examination confirms the elemental composition of Sb (41.79 %) and O (58.21 %) in Sb₂O₃ and Sb (36.80 %), O (58.95 %), and Ni (4.25 %) in Ni–Sb₂O₃. Sb₂O₃ and Ni– Sb₂O₃ exhibit band gaps of 3.67 eV and 3.51 eV, respectively, according to UV–Vis analysis. The IR peaks 445.47, 642.18, and 745.18 in Sb₂O₃ and 438.72, 645.07, and 756.92 in Ni– Sb₂O₃ support the Sb–O bonding in the synthesized nanomaterials. The synthesized nanomaterials have been used for photocatalytic degradation of malachite green (MG) dye and sensing NO₂, SO₂, CO₂, petroleum vapour and LPG gases. The MG dye was degraded 97.67 % in 120 min using Ni–Sb₂O₃ at optimized conditions (catalyst dose: 0.1 g/L to 0.3 g/L, pH: 7 and MG dye: 10 ppm). The gas sensing study showed that Ni–Sb₂O₃ sensor has greater sensitivity and selectivity for NO₂ gas.