N. Clament Sagaya Selvam

Comparative investigation of zirconium oxide (ZrO2) nano and microstructures for structural, optical and photocatalytic properties.

ZrO(2) nanocrystals were synthesized by the microwave combustion method (MCM) using urea as the fuel without using any template, catalyst or surfactant. For the purpose of comparison, it was also prepared using the conventional combustion method (CCM). The as-synthesized ZrO(2) was characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The results indicated that the ZrO(2) nanocrystals obtained by MCM show high crystallinity and uniform size distribution than the ones prepared by CCM. Hence, the influence of the preparation methods on the structure, morphology and optical activity of ZrO(2) was investigated systematically. Photocatalytic degradation (PCD) of 4-Chlorophenol (4-CP), a potent endocrine disrupting chemical in aqueous medium was investigated by ZrO(2) nanocrystals obtained by MCM. The kinetics of PCD was found to follow pseudo first-order. Having established that ZrO(2) was photo catalytically active, the mixed oxide catalysts of ZrO(2)-TiO(2) were also tested for the PCD of 4-CP.

Pure and Mg-doped self-assembled ZnO nano-particles for the enhanced photocatalytic degradation of 4-chlorophenol

A novel self-assembled pure and Mg doped ZnO nano-particles (NPs) were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffraction, high resolution scanning electron microscopy, high resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The results indicated that the prepared photocatalysts showed high crystallinity with a uniform size distribution of the NPs. The degradation of cholorphenols is highly mandatory in todays scenario as they are affecting the environment adversely. Thus, the photocatalytic degradation of 4-chlorophenol (4-CP), a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and Mg-doped ZnO NPs under UV-light irradiation in the present study. The influence of the Mg content on the structure, morphology, PL character and photocatalytic activity of ZnO NPs were investigated systematically. Furthermore,the effect of different parameters such as 4-CP concentration, photocatalyst amount, pH and UV-light wavelength on the resulting photocatalytic activity was investigated.

Comparative studies on influence of morphology and La doping on structural, optical, and photocatalytic properties of zinc oxide nanostructures

A simple, low temperature co-precipitation method was developed to synthesize ZnO nanomaterials with different morphologies such as nanoflakes, spherical nanoparticles (SNPs), and nanorods. The concentration of the capping agent, Triton X-100, is a key factor in the morphological control of ZnO nanostructures. The formation of different morphologies of ZnO was confirmed by HR-SEM and HR-TEM. XRD data showed the formation of single-phase ZnO with the wurtzite crystal structure. The influence of La contents on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO SNPs was investigated systematically. The influence of the ZnO morphologies on the photocatalytic degradation (PCD) of Bisphenol A (BPA) as a model reaction is evaluated and discussed in terms of surface area, crystal growth habits, particle size, and oxygen defects. The results indicated that the particle size is an important factor for the enhancement of PCD. Furthermore, the effect of different photocatalytic reaction parameters on the resulting PCD efficiency of ZnO SNPs was investigated.

Effects of Ba doping on structural, morphological, optical, and photocatalytic properties of self-assembled ZnO nanospheres

A simple low-temperature co-precipitation method was employed to synthesize pure and Ba-doped self-assembled ZnO nanospheres. The presence of self-assembled nanosphere-like morphology, high crystallinity, uniform size distribution, and more defects were confirmed by X-ray diffraction, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. Photocatalytic degradation of 2,4,6-trichlorophenol, a potent endocrine-disrupting chemical in aqueous medium was investigated. The effects of Ba doping on the structure, morphology, absorption, emission, and photocatalytic activity of ZnO nanospheres were investigated systematically. Furthermore, the effects of different photocatalytic degradation reaction parameters were investigated. The resulting photocatalytic degradation activity of Ba-doped ZnO nanospheres shows superior efficiency compared to pure ZnO and commercial TiO2 (Degussa P-25).Graphical AbstractA simple co-precipitation method was developed to synthesize pure and Ba-doped ZnO self-assembled nanospheres. The prepared photocatalyst shows a novel morphology, high crystallinity, uniform size distribution, and more defects. Effect of Ba doping on the structural, optical and photocatalytic properties of ZnO nanospheres were investigated systematically.