Fine control over the morphology and photocatalytic activity of 3D ZnO hierarchical nanostructures: capping vs. etching

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56232-56238 ◽  
Author(s):  
Jawayria Mujtaba ◽  
Hongyu Sun ◽  
Fang Fang ◽  
Mashkoor Ahmad ◽  
Jing Zhu

ZnO 3D hierarchical structures with different morphologies can be selectively synthesized at room temperature by using potassium hydroxide and citric acid as an etchant and capping agent, respectively.

2008 ◽  
Vol 8 (12) ◽  
pp. 6355-6360
Author(s):  
Ahmad Umar ◽  
A. Al. Hajry ◽  
S. Al-Heniti ◽  
Y.-B. Hahn

Growth of hierarchical ZnO nanostructures composed of ZnO nanoneedles have been achieved via simple thermal evaporation process by using metallic zinc powder in the presence of oxygen at low temperature of 460 °C on silicon substrate without the use of any kind of metal catalysts or additives. It is confirmed by detailed structural studies that the as-grown hierarchical nanostructures are single crystalline with a wurtzite hexagonal phase and nanoneedles of these structures are grown along the c-axis in the [0001] direction. The Raman-scattering analysis substantiates a wurtzite hexagonal phase with a good crystal quality for the as-grown products. Room-temperature photoluminescence (PL) exhibits a strong UV emission at 380 nm confirming the excellent optical properties of as-synthesized hierarchical structures. A plausible growth mechanism is also proposed to clearly understand the growth process of the synthesized structures.


2019 ◽  
Vol 9 (3) ◽  
pp. 362-370 ◽  
Author(s):  
D. Vaya ◽  
Meena ◽  
B.K. Das

Background: The properties of the material are altered when material size shifted towards nano-regime. This feature could be used for wastewater treatment process using model pollutant such as dyes. Recently, nanoparticles are synthesized by a green chemical route using different capping agents. This is the reason we adopt starch as green capping agent along with sol-gel method. Objective: To synthesize cobalt oxide nanoparticles by green chemical route and utilized it in degradation of dyes. Methods: Synthesis of cobalt oxide nanoparticles by sol-gel method using starch as a capping agent. The characteristics of surface modifications were investigated by UV-VIS, TEM, SEM, XRD and FTIR techniques. Results: Cobalt oxide nanoparticles synthesized and inhibited photocatalytic activity. Conclusion: Deactivation of photocatalytic activity due to complex nature of starch. This property can be used elsewhere as in light shielding applications to coat and protect surfaces in order to keep them cool and safe from damage as in the painting of vehicles, roofs, buildings, water tanks, etc.


2021 ◽  
Author(s):  
Lifang Qi ◽  
Yao Le ◽  
Chao Wang ◽  
Rui Lei ◽  
Tian Wu

Self-assembling ultrathin active δ-MnO2 nanosheets and Mn3O4 octahedrons into hierarchical texture enhances room-temperature formaldehyde oxidation at a low-level of Pt.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.


Sign in / Sign up

Export Citation Format

Share Document