Green emission of indium oxide <i>via</i> hydrogen treatment

Arooj, Syeda; Xu, Tingting; Hou, Xudong; Wang, Yang; Tong, Jing; Chu, Ruiai; Liu, Bo

doi:10.1039/c8ra00654g

Cited by 38 publications

(35 citation statements)

References 49 publications

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“…19a). The rising baseline in the near infrared spectral range could be caused by free electrons in the conduction band, generated by the homolytic splitting of H 2 30 . The absence of indium hydrides in the region of 1100−4000 cm −1 implies homolysis of H 2 , which is different from the former study over In 2 O 3−x (OH) y that exhibited heterolysis of H 2 31 .…”

Section: How Does Black Indium Oxide Function As a Photocatalyst?mentioning

confidence: 99%

Black indium oxide a photothermal CO2 hydrogenation catalyst

et al. 2020

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Nanostructured forms of stoichiometric In 2 O 3 are proving to be efficacious catalysts for the gas-phase hydrogenation of CO 2. These conversions can be facilitated using either heat or light; however, until now, the limited optical absorption intensity evidenced by the pale-yellow color of In 2 O 3 has prevented the use of both together. To take advantage of the heat and light content of solar energy, it would be advantageous to make indium oxide black. Herein, we present a synthetic route to tune the color of In 2 O 3 to pitch black by controlling its degree of non-stoichiometry. Black indium oxide comprises amorphous non-stoichiometric domains of In 2 O 3-x on a core of crystalline stoichiometric In 2 O 3 , and has 100% selectivity towards the hydrogenation of CO 2 to CO with a turnover frequency of 2.44 s −1 .

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Section: How Does Black Indium Oxide Function As a Photocatalyst?mentioning

confidence: 99%

Black indium oxide a photothermal CO2 hydrogenation catalyst

et al. 2020

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“…The peak at 132 cm −1 is attributed to the In-O vibration of [InO6] structural units, the peak at 307.7 cm −1 is due to the bending vibration of the δ-[InO6] octahedrons, Characteristic Raman vibrational modes corresponding to the body-centered cubic In 2 O 3 are observed at 132, 307.7, 366.7, 494.6, and 628.5 cm −1 and their positions are in agreement with previously reported data [44][45][46]. The peak at 132 cm −1 is attributed to the In-O vibration of [InO 6 ] structural units, the peak at 307.7 cm −1 is due to the bending vibration of the δ-[InO 6 ] octahedrons, the peaks at 494.6 and 628.5 cm −1 are assigned to the stretching vibrations of the ν-[InO 6 ] octahedrons, and the peak at 366.7 cm −1 is attributed to the stretching vibrations of the In-O-In bonds [47][48][49]. The broad peak at 458 cm −1 probably has the same nature as SnO 2 wide band at 563 cm −1 corresponding to a local structural defects due to small particle size of nanocrystalline In 2 O 3 [50].…”

Section: Characteristics Of Nanocrystalline Semiconductor Oxidesmentioning

confidence: 99%

“…Nanomaterials 2020, 10, x FOR PEER REVIEW 7 of 23 the peaks at 494.6 and 628.5 cm −1 are assigned to the stretching vibrations of the ν-[InO6] octahedrons, and the peak at 366.7 cm −1 is attributed to the stretching vibrations of the In-O-In bonds [47][48][49]. The broad peak at 458 cm −1 probably has the same nature as SnO2 wide band at 563 cm −1 corresponding to a local structural defects due to small particle size of nanocrystalline In2O3 [50].…”

Section: Characteristics Of Ru (Ii) Heterocyclic Complexmentioning

confidence: 99%

Organic-Inorganic Hybrid Materials for Room Temperature Light-Activated Sub-ppm NO Detection

et al. 2019

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Nitric oxide (NO) is one of the main environmental pollutants and one of the biomarkers noninvasive diagnosis of respiratory diseases. Organic-inorganic hybrids based on heterocyclic Ru (II) complex and nanocrystalline semiconductor oxides SnO 2 and In 2 O 3 were studied as sensitive materials for NO detection at room temperature under periodic blue light (λ max = 470 nm) illumination. The semiconductor matrixes were obtained by chemical precipitation with subsequent thermal annealing and characterized by XRD, Raman spectroscopy, and single-point BET methods. The heterocyclic Ru (II) complex was synthesized for the first time and characterized by 1 H NMR, 13 C NMR, MALDI-TOF mass spectrometry and elemental analysis. The HOMO and LUMO energies of the Ru (II) complex are calculated from cyclic voltammetry data. The thermal stability of hybrids was investigated by thermogravimetric analysis (TGA)-MS analysis. The optical properties of Ru (II) complex, nanocrystalline oxides and hybrids were studied by UV-Vis spectroscopy in transmission and diffuse reflectance modes. DRIFT spectroscopy was performed to investigate the interaction between NO and the surface of the synthesized materials. Sensor measurements demonstrate that hybrid materials are able to detect NO at room temperature in the concentration range of 0.25-4.0 ppm with the detection limit of 69-88 ppb.Nanomaterials 2020, 10, 70 2 of 22 in noninvasive diagnosis of respiratory diseases [7][8][9]. In this case, the limitation of the quantitative determination of NO in exhaled air is due to the low level of its concentration (20-200 ppb) among a wide range of interfering gases [10].Direct determination of nitrogen monoxide in the gas phase is possible using conductometric gas sensors based on various semiconductor metal oxides [7,[10][11][12][13][14][15][16][17][18][19][20][21][22]. To increase selectivity of such analysis along with lower power consumption, complete or partial replacement of thermal heating with photoactivation is a promising approach. Activation of the sensor response under illumination occurs through various mechanisms depending on the nature of the target gas. For oxidizing gases (NO 2 , O 3 ), which compete with oxygen for the same adsorption sites, photogeneration of electron-hole pairs plays a major role in the photodesorption process. On the contrary, for the detection of reducing gases (CO, NH 3 , H 2 S), the presence of chemisorbed oxygen on the surface of the semiconductor oxide is necessary. In this case, the increase in the sensor response under illumination is due to the unpinning of Fermi level of the semiconductor. In most works NO is detected as oxidizing gas. The similar routes of NO and NO 2 sensing was recently evidenced by in situ DRIFT spectroscopy [23]. Our previous works show that highly selective NO 2 detection is possible using visible light photoactivation [24][25][26][27]. To shift the optical sensitivity of semiconductor oxides into the visible range, it is necessary to create defects in the semiconductor matrix or i...

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“…Peak 4 was included in the luminescence range of the In 2 O 3 particle [ 20 ]. All peaks in the visible light region are believed to originate from the defects in the structure of indium oxide [ 5 , 9 , 11 , 23 , 24 , 25 , 26 ]. This strong emission peak could be the evidence for the existence of defects, contributing to the lower resistivity and the degenerate semiconductor behavior.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of High-Density Indium Oxide Nanowires with Low Electrical Resistivity

Chen

Yang

2020

Nanomaterials

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In this study, indium oxide nanowires of high-density were synthesized by chemical vapor deposition (CVD) through a vapor–liquid–solid (VLS) mechanism without carrier gas. The indium oxide nanowires possess great morphology with an aspect ratio of over 400 and an average diameter of 50 nm; the length of the nanowires could be over 30 μm, confirmed by field-emission scanning electron microscopy (SEM). Characterization was conducted with X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence spectrum (PL). High-resolution TEM studies confirm that the grown nanowires were single crystalline c-In2O3 nanowires of body-centered cubic structures. The room temperature PL spectrum shows a strong peak around 2.22 eV, originating from the defects in the crystal structure. The electrical resistivity of a single indium oxide nanowire was measured to be 1.0 × 10−4 Ω⋅cm, relatively low as compared with previous works, which may result from the abundant oxygen vacancies in the nanowires, acting as unintentional doping.

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Green emission of indium oxide via hydrogen treatment

Abstract: H2-treated In2O3 gives rise to photoemission ranging from blue to green-yellow, while air-calcined In2O3 shows only blue emission. EPR and optical spectroscopies reveal singly ionized oxygen vacancies induced by H2 treatment responsible for the green-yellow emission.

Cited by 38 publications

References 49 publications

Black indium oxide a photothermal CO2 hydrogenation catalyst

Black indium oxide a photothermal CO2 hydrogenation catalyst

Organic-Inorganic Hybrid Materials for Room Temperature Light-Activated Sub-ppm NO Detection

Synthesis of High-Density Indium Oxide Nanowires with Low Electrical Resistivity

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