Electron Beam Modulated Wettability and Electrical Conductivity of Hydrogen Titanate Nanowires

Abstract

The effect of electron irradiation on the chemical and physical properties of surfaces is an extremely crucial field of study in the context of space exploration, radiation chemistry, and physics. For instance, long-term ion and electron irradiations in planetary or satellite surfaces lead to a significant change in surface and environmental compositions. In this work the modification of hydrogen titanate nanowires using low energy electrons has been studied. The nanowires are initially strongly hydrophilic, which changes to hydrophobic after electron irradiation. The electrical conductivity of the nanowires increases systematically with irradiation dose. We have invoked first-principles-based calculations to explain the observed results. The calculation shows that the removal of OH groups from the layered structure due to irradiation influences the wetting property. Furthermore, the irradiation-induced defects lead to an empty Ti d-shell near the Fermi level, which contributes toward the modification of electrical conductivity. The theoretical predictions are also corroborated with Xray diffraction, X-ray electron spectroscopic, and Raman scattering spectroscopic studies, respectively.

Methyl Group-Promoted Generation of Oxygen Vacancies in an Aerobically Annealed TiO2 Nanostructure for Photocatalytic H2 Production

“…42−45 Herein, the Raman spectra, together with the XRD measurements described above, clearly support that when the calcination temperature is increased from 100 to 300 °C, the possible processes, such as the dehydration triggered by the break of the hydroxyl groups, the disruption of Ti−O bonds in the basic unit, and the reestablishment of a new network, occurred and thus led to the significant variation of the Raman spectra, including shape and intensity of the bands. 46,47 With increasing the calcination temperature to 400 °C, several well-known intensive anatase peaks located at 143, 196, 397, 516, and 640 cm −1 dominate the spectrum at this stage, suggesting the final phase transformation and enhanced crystallinity, which is in accordance with the corresponding XRD patterns shown in Figure 2.…”

“…Since Raman spectroscopy is particularly sensitive to subtle bond vibration or crystal structure change caused by the phase transition and defect formation, more abrupt changes were thus observed in the Raman spectrum than in the XRD patterns. Moreover, it has been demonstrated that the intensity and shape of Raman spectra are strongly influenced by the phonon confinement effect, defects, and lattice strain. − Herein, the Raman spectra, together with the XRD measurements described above, clearly support that when the calcination temperature is increased from 100 to 300 °C, the possible processes, such as the dehydration triggered by the break of the hydroxyl groups, the disruption of Ti–O bonds in the basic unit, and the re-establishment of a new network, occurred and thus led to the significant variation of the Raman spectra, including shape and intensity of the bands. , With increasing the calcination temperature to 400 °C, several well-known intensive anatase peaks located at 143, 196, 397, 516, and 640 cm –1 dominate the spectrum at this stage, suggesting the final phase transformation and enhanced crystallinity, which is in accordance with the corresponding XRD patterns shown in Figure .…”

Water-repelling behavior of the 1-D hematite nano-network

“…Amorphization of the nanostructured samples induced by ion irradiation is a well-known phenomenon. 63 The accumulation of large number of defects induced by ion collision may cause amorphization, and the extent of amorphization increases with the ion fluence. The ion collision triggers the diffusion of vacancies and interstitials.…”

Core–Shell Nanostructures of Tungsten Oxide and Hydrogen Titanate for H2 Gas Adsorption

“…As can be seen, the pristine structure has a bandgap of 0.63 eV, and the irradiated structure with O vacancy in WO 3 has a bandgap of 0.37 eV. However, the irradiated structures with the vacancy in HTNTs behave like metallic structures due to the oxygen and titanium vacancies and formation of the Ti 3+ state, which is accountable for the bandgap narrowing. ,, The reduction in bandgap causes significant modifications in the electrical conductivity and is appropriate for sensor design. The H 2 molecule has a better affinity for the irradiated system with the O vacancy in HTNTs, with the maximum adsorption energy, relatively short bonding distance, good amount of charge transfer, and lowest bandgap value of all configurations, making the irradiated structure an excellent candidate for H 2 gas sensing application.…”