Fabrication of High Surface Area Microporous ZnO from ZnO/Carbon Sacrificial Composite Monolith Template

Abstract

Fabrication of porous materials from the standard sacrificial template method allows metal oxide nanostructures to be produced and have several applications in energy, filtration and constructing sensing devices. However, the low surface area of these nanostructures is a significant drawback for most applications. Here, we report the synthesis of ZnO/carbon composite monoliths in which carbon is used as a sacrificial template to produce zinc oxide (ZnO) porous nanostructures with a high specific surface area. The synthesized porous oxides of ZnO with a specific surface area of 78 m2/g are at least one order of magnitude higher than that of the ZnO nanotubes reported in the literature. The crucial point to achieving this remarkable result was the usage of a novel ZnO/carbon template where the carbon template was removed by simple heating in the air. As a high surface area porous nanostructured ZnO, these synthesized materials can be useful in various applications including catalysis, photocatalysis, separation, sensing, solar energy harvest and Zn-ion battery and as supercapacitors for energy storage.

Development of Tetrapod Zinc Oxide-Based UV Sensor for Precision Livestock Farming and Productivity

“…Based on the ZnO sensor’s surface, when adsorbed molecular oxygen under UV activation captures photogenerated free electrons, they result in the chemisorption of oxygen ions to ZnO surface following: O 2 (g) + e − →O 2 − (ads) or O 2 (g) + e − →2O − (ads), leaving photo-induced holes in the low-conductivity depletion layer (or space charge region, SCR). According to the space charge model [ 25 , 54 ], there will be upward band-bending near the surface for both the conduction and valence bands shown in Figure 5 a. As a result, there is an increase in energy barrier height for electron transfer between the grains or across neighboring T–ZnO arms, i.e., the qV s1 , and thus the overall conductance is reduced (alternatively, increasing resistance).…”

“…T–ZnO has also shown improved carrier mobility over zero-dimensional (0D) nanostructures, resulting in faster response and recovery times, comparable to those of one-dimensional (1D) nanostructures [ 8 , 24 ]. It also has a wide-ranging BET surface area, which can vary anywhere between 5 and 78 m 2 /g depending upon the morphological structure [ 25 , 26 ]. Thepnurat et al fabricated UV sensors utilizing interconnected T–ZnO that showed promising results due to the linked tetrapod arms, which decrease the potential barrier at grain boundaries, thereby improving UV-induced charge carrier mobility [ 20 ].…”