Aero-TiO2 Prepared on the Basis of Networks of ZnO Tetrapods

Abstract

In this paper, new aeromaterials are proposed on the basis of titania thin films deposited using atomic layer deposition (ALD) on a sacrificial network of ZnO microtetrapods. The technology consists of two technological steps applied after ALD, namely, thermal treatment at different temperatures and etching of the sacrificial template. Two procedures are applied for etching, one of which is wet etching in a citric acid aqua solution, while the other one is etching in a hydride vapor phase epitaxy (HVPE) system with HCl and hydrogen chemicals. The morphology, composition, and crystal structure of the produced aeromaterials are investigated depending on the temperature of annealing and the sequence of the technological steps. The performed photoluminescence analysis suggests that the developed aeromaterials are potential candidates for photocatalytic applications.

Aero-ZnS prepared by physical vapor transport on three-dimensional networks of sacrificial ZnO microtetrapods

“…The formation of the SnO 2 phase in the prepared aero-ZnS materials revealed by XRD and PL spectral analyses (Figure 7) may be beneficial from the point of view of preparing various nanocomposites in a controlled manner, providing opportunities for bandgap engineering. This approach is interesting for the alignment of the conduction and valence bands of the nanocomposite components with respect to the HOMO and LUMO molecular orbitals of organic compounds subjected to photocatalytic degradation [18,44]. Specific photocatalytic properties of the aero-ZnS materials prepared by physical vapor transport have not been investigated in this paper.…”

“…The duration of the technological procedure was four and eight hours. This technological installation is less sophisticated and, consequently, less expensive than the equipment for HVPE previously used for the preparation of aero-semiconductor materials [11][12][13][14][15][16][17][18], including aero-ZnS materials [16]. The HVPE installation consists of two chambers.…”

“…Among porous semiconductor materials, recently developed super-lightweight ones with ultrahigh degree of porosity, the so-called aeromaterials, are of special interest [11][12][13][14][15][16][17][18]. Aeromaterials are similar to aerogels, which are widely explored and used in various applications.…”

“…Sacrificial porous ZnO networks of microtetrapods have also been used for the preparation of the abovementioned semiconductor-based aeromaterials. Most of these aeromaterials have been produced by hydride vapor phase epitaxy (HVPE) [11][12][13][14][15][16][17][18]. Particularly, an aero-ZnS material exhibiting hydrophilic properties under tension and hydrophobic properties when compressed against water was fabricated using HVPE of CdS on sacrificial ZnO microtetrapods through the simultaneous or subsequent transformation of CdS into ZnS and the removal of the sacrificial ZnO crystals [16].…”

Porous Semiconductor Compounds with Engineered Morphology as a Platform for Various Applications

“…[22] Incorporation of semiconductor nanoparticles into aerogels was also proposed as an efficient strategy for improving their efficiency in various applications. [23,24] At the same time, a new series of semiconductor aero-materials is also emerging [25] on the basis of carbon foams. [26] As compared to these classes of nanomaterials, inorganic porous compound semiconductors are less explored.…”