Large Scale Synthesis of ZnO Nanostructures of Different Morphologies through Solvent-free Mechanochemical Synthesis and their Application in Photocatalytic Dye Degradation

Abstract

Well crystalline, near-stoichiometric zinc oxide nanostructures of different morphologies are fabricated in large scale, utilizing a simple, cost effective mechanochemical synthesis in absence of solvent. Effects of ionic and nonionic surfactants along with the concentration of hydrolyzing agent on the evolution of nanostructure morphology have been studied. It has been observed that while a cationic surfactant such as Cetyltrimethylammonium Bromide (CTAB) favors the nanostructures to growth along their polar c-axis, a nonionic surfactant such as Polyvinylpyrrolidone (PVP) reduces their preferred c-axis growth. Increase of hydrolyzing agent in the reaction mixture enhances the growth rate of the nanostructures. The nanostructures have been tested for photodegradation of anionic dye molecules such as Methylene Blue (MB). All the nanostructures manifest high photocatalytic performance. Apart from morphology, the specific surface area, crystal plane orientation and the concentration of basic sites at surface are seen to contribute significantly to the photocatalytic performance of the zinc oxide nanostructures.

The role of NaOH content, grinding time, and drying temperature in controlling the shape and size of nano ZnO synthesized by a green chemistry approach

“…The previous equation showed the preparation of zinc hydroxide [66] while Zeferino et al [67] recorded the direct production of tetrahydroxozincate [Zn(OH) 4 ] 2in highly basic condition (abundant NaOH). In solid-state reaction, the phase transition or what is called phase transformation (crystal growth) was illustrated by Mnyukh [68].…”

“…complete conversion to zinc oxide occurs during the drying step using a hot air oven (equations 1&2). It is expected that partial conversion occurs during grinding step as a result of heat released by the grinding process itself [66,67] and by NaOH as an exothermic substance. concerning the size, the current results revealed the increase in the growth rate of rodshaped particles by increasing NaOH that reached their maximum length when the mole ratio of D. Refaat et al…”

“…(ZnSO 4 .7H 2 O: NaOH) was 1:8. Zeferino et al [67] explained that the increase in NaOH in the reaction mix causes a decrease in surface tension that in turn fostering the growth rate of ZnO.…”

Nitrogen-Doped Carbon Dots Induced Enhancement in CO2 Sensing Response From ZnO–Porous Silicon Hybrid Structure

“…Finally, the obtained sample (denoted as ZnO-pSi sample) was thermally treated at 550 • C for 6 h in air. The reaction path for the formation of ZnO nuclei in a basic medium can be described through [Equations 1-3; (Morales Flores et al, 2014;Sánchez Zeferino et al, 2016;Karthik et al, 2018)]:…”

The TESS Satellite will Search for Planets in the Vicinity of our Solar System

“…During the four years of the first mission, the ship scanned 150,000 stars, searching for the small falls in light caused by planets that pass in front of them. In 2014, Kepler switched to the second mission called K2, where he still hunts planets but also makes a variety of observations (Wang and Yagi, 2016;Obaiys et al, 2016;Ahmed et al, 2016;Jauhari et al, 2016;Syahrullah and Sinaga, 2016;Shanmugam, 2016;Jaber and Bicker, 2016;Moubarek and Gharsallah, 2016;Amani, 2016;Shruti, 2016;Pérez-de León et al, 2016;Mohseni and Tsavdaridis, 2016;Abu-Lebdeh et al, 2016;Serebrennikov et al, 2016;Budak et al, 2016;Augustine et al, 2016;Jarahi and Seifilaleh, 2016;Nabilou, 2016;You et al, 2016;Zurfi and Zhang, 2016;Rama et al, 2016;Sallami et al, 2016;Huang et al, 2016;Ali et al, 2016;Kamble and Kumar, 2016;Saikia and Karak, 2016;Zeferino et al, 2016;Pravettoni et al, 2016;Bedon and Amadio, 2016;Chen and Xu, 2016;Mavukkandy et al, 2016;Yeargin et al, 2016;Madani and Dababneh, 2016;Alhasanat et al, 2016;Elliott et al, 2016;Suarez et al, 2016;Kuli et al, 2016;…”