Effect of induced defects on the properties of ZnO nanocrystals: surfactant role and spectroscopic analysis

Abstract

Semiconductor photocatalysts are one of the major sought area of research due to their extensive use in the degradation of organic pollutants under UV-visible and solar light. Herein, we are reporting the synthesis of microscopic spindle shaped ZnO photocatalysts with different reducing agents such as sodium hydroxide, hydrazine hydride, sodium borohydride and lithium triethyl borohydride. These spindle shaped ZnO are synthesized by facile soft chemical approach by varying reducing agents with fixed molar ratio at 1:2 zinc precursor to reducing agents. These ZnOs were thoroughly characterised by various sophisticated characterization techniques such as XRD, FTIR, SEM, and HRTEM, Raman and ESR spectroscopies. Microscopic results show that these ZnO show similar fusiform morphologies with the variation in sizes and their distributions, and hence possess different defect related properties. The structural growth mechanism and defect related properties were explained on the basis of different reducing abilities of reducing agents (different reaction pH) and their nucleation with the aid of morphological analysis, and ESR analysis. Furthermore, the photocatalytic activity of these spindle shaped ZnO were evaluated against two cationic dyes (methylene blue dyes, Rhodamine B) under UV light. The photocatalytic results show that these spindle shaped ZnO are very effective for the photo-catalytic degradation of methylene blue and rhodamine B dye under the illumination of UV light.

Microwave assisted synthesis of zinc oxide (ZnO) nanoparticles in a noble approach: utilization for antibacterial and photocatalytic activity

“…From the FT-IR spectrum, various functional groups and metaloxide (MO) bond present in the compound were analyzed. In the FTIR spectrum, three sharp peaks were observed at 557.43 cm −1 ,498.92 cm −1 and 524.64 cm −1 , which could be attributed to the Zn-O stretching vibration mode which is consistent with other report [40]. In these cases, variation of ZnO stretching vibrational mode was observed because the number of atoms that constitute the surface might be changed at different conditions.…”

Eco-Friendly Photocatalysts for Degradation of Dyes

“…Indirectly, the photocatalytic activity of the catalysts is affected since OH radicals at the ZnO (R) surface are more difficult to attack the pollutant molecules. This will then cause the degradation rate to decrease [45]. To quantify differences in degradation rates, degradations of MB dye were employed to obtain pseudo first-order kinetic constants as shown in Figure 9b.…”

Development of highly sensitive Al, Ga, and In-doped ZnO films by the drop casting method for NH3 gas sensing

“…The band frequencies at around 860 cm À1 indicate the O-H bending of the hydroxyl group. 32 The vibrational peaks observed around 1600 cm À1 and 1415 cm À1 were attributed to the CQO (symmetric and asymmetric) stretching and carboxylic O-H bending, respectively. The peak at 2932 cm À1 was due to C-H stretching vibrations.…”