A review on biological synthesis of ZnO nanostructures and its application in photocatalysis mediated dye degradation: An overview

Abstract

Zinc oxide (ZnO) has several industrial applications due to its versatile properties, which lead to its continuously increasing demand in different industrial sectors. Additionally, ZnO nanostructures possess unique photocatalytic activity, and because of this, they are being applied to degrade organic dyes through photocatalysis for wastewater treatment. Nevertheless, chemical synthesis methods to develop ZnO nanostructures have raised concerns related to environmental issues, furthermore, these methods are found to be costly and tedious. As a result, the synthesis of ZnO nanostructures using green methods is gaining popularity due to its low cost and eco‐friendly mode, while avoiding the use of toxic chemicals. Green synthesis of ZnO nanostructures using different biological approaches involving plants, algae, and different microorganism‐derived bioactive compounds has been well reported for diverse applications. Among different applications, ZnO nanostructures that enable photocatalysis to degrade dye have been found to be imperative for wastewater treatments. Therefore, the current review explores recent studies on green synthesis approaches to prepare ZnO nanostructures via adopting different biological methods that rely on plants, algae, and bacterial microorganisms. The properties of ZnO nanostructures, along with their green synthesis routes and feasible mechanisms, have also been discussed in this review. This review focuses on the use and efficiency of green route synthesized ZnO nanostructures as nanophotocatalysts for the degradation of organic dyes in wastewater treatment. Additionally, existing challenges in green synthesis methods and the efficiency of ZnO nanostructures to degrade organic dyes following photocatalysis has been discussed.

Smart and intelligent optical materials for sensing applications

“…Furthermore, the author also highlighted different biosensors fabricated during the COVID‐19 pandemic. Mohammed [27] briefly discussed the synthesis route and feasible mechanism of nanostructured ZnO using green synthesis methods via various biological techniques and bacterial microorganisms, algae, and plants. An insight into the efficacious green production of nano zinc oxide (Zn) and its utilization in effluent treatment was also provided.…”

Accelerating carrier separation to boost the photocatalytic CO2 reduction performance of ternary heterojunction Ag–Ti3C2Tx/ZnO catalysts

“…ZnO is a direct bandgap semiconductor with a bandgap width of 3.37 eV and has superior photocatalytic activity in the ultraviolet region, which means that most of the sunlight cannot be fully utilized, seriously affecting the photocatalytic efficiency of ZnO photocatalysts. [25][26][27] In addition, the rapid complexation of carriers is also an important reason hindering the improvement of the photocatalytic activity of ZnO. Therefore, for ZnO-based photocatalysts, expanding their visible light absorption range and promoting the separation of photogenerated electron-hole pairs can be benecial to enhance their photocatalytic performance.…”

Bioinspired Fibrous Architectures Based on ZnO Templated by Eggshell Membranes

“…Over the last decades, zinc oxide (ZnO) has been extensively and intensively assessed attracting an enormous interest from both science and industry. Thus, ZnO micro/nanostructures emerge as a powerful class of advanced functional materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], which can find applications in various domains ranging from electronics, energy, and environmental protection to healthcare. Recently, a large number of comprehensive review papers provide synopses on the recent achievements attained in the preparation and properties of ZnO nanomaterials and their use in electronic devices [8], UV photodetectors [9], photovoltaic devices [10], gas sensors [11], nonlinear optical materials [12], biosensors [13,14], photocatalysis [15][16][17], antibacterial agents [18,19], surface coating with special wetting properties [20], and so on.…”