Bandgap tuning and XPS study of SnO2 quantum dots

Babu, B. Hari; Reddy, I. Neelakanta; Yoo, Kisoo; Kim, Dongseob; Shim, Jaesool

doi:10.1016/j.matlet.2018.03.107

Cited by 110 publications

(55 citation statements)

References 15 publications

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“…The weak C peak is attributed to adventitious carbon adsorbed on the surface of the samples as a contaminant, and the C 1s binding energy of 284.7 eV was used as the reference for calibration. As shown in the Sn 3d spectrum in Figure 5b, the two nearly symmetric peaks located at 494.9 eV and 486.5 eV are attributed to Sn 3d 3/2 and Sn 3d 5/2 of Sn 2+ , respectively [17,19], indicating the presence of Sn 2+ in SNM-8. More accurate scans of the Ni 2p 3/2 of the pure NiO and SNM-8 are shown in Figure 5c and Figure 5d, respectively.…”

Section: Resultsmentioning

confidence: 99%

Highly Selective, ppb-Level Xylene Gas Detection by Sn2+-Doped NiO Flower-Like Microspheres Prepared by a One-Step Hydrothermal Method

Zheng

et al. 2019

Sensors

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Detecting xylene gas is an important means of avoiding human harm from gas poisoning. A precise measurement demands that the gas sensor used must have high sensitivity, high selectivity, and low working temperature. To meet these requirements, in this study, Sn2+-doped NiO flower-like microspheres (SNM) with different amounts of Sn2+ synthesized by a one-step hydrothermal process were investigated. The responses of gas sensors based on different Sn2+-doped NiO materials for various targeting gases were fully characterized. It was found that all of the synthesized materials exhibited the best gas response at a working temperature of 180 degrees, which was much lower than the previously reported working temperature range of 300–500 degrees. When exposed to 10 ppm xylene, the 8 at% Sn2+-doped NiO sensor (mol ratio) exhibited the highest response, with a value of 30 (Rg/Ra). More significantly, the detection limit of the 8 at% Sn2+-doped NiO sensor for xylene is down in the ppb level. The Sn2+-doped NiO material also exhibits excellent selectivity for other gases with long-term stability and repeatability. The significant improvement in the response to xylene can theoretically be attributed to a decrease in the intrinsic hole carrier concentration, higher amounts of adsorbed oxygen and active sites.

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Section: Resultsmentioning

confidence: 99%

Highly Selective, ppb-Level Xylene Gas Detection by Sn2+-Doped NiO Flower-Like Microspheres Prepared by a One-Step Hydrothermal Method

Zheng

et al. 2019

Sensors

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“…The peaks centered at 486.65 eV, 486.77 eV, and 486.58 eV correspond to the Sn5/2 peaks, which were obtained in blank solution, with 10 −4 M Cys and with 10 −2 M Cys, respectively (Figure 7b). In all cases, the peak values correspond to ionic tin (Sn 4+ ) [39,[52][53][54][55][56], which may indicate the formation of the compound of Sn on the alloy surface, meaning, therefore, the contribution of Sn 2+ to the surface film should not be ignored. In addition to the main Sn3d peaks, satellite peaks at higher binding energies of 499.05 and 499.08 eV appear for the blank and the surface-inhibited surface with lower Cys concentration (10 −4 M), respectively, which may be attributed to the presence of more tin ion contents on the alloy surface [57].…”

Section: Xps and Auger Resultsmentioning

confidence: 99%

The Protection Role of Cysteine for Cu-5Zn-5Al-1Sn Alloy Corrosion in 3.5 wt.% NaCl Solution

et al. 2019

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In this work, the corrosion mechanism of a Cu-5Zn-5Al-1Sn alloy was examined in a 3.5 wt.% NaCl solution. At the same time, the effect of a cysteine inhibitor was also investigated through a multi-analytical approach. Electrochemical results suggested that inhibition efficiency increased with the increase of cysteine concentration. From potentiodynamic polarization (PD) analysis, a decrease in corrosion current and corrosion potential shift toward a more negative direction was observed. The potential difference between the blank and inhibited surface was found to be 46 mV, which is less than 85 mV, revealing a mixed type inhibition effect of cysteine for the Cu-5Zn-5Al-1Sn alloy. The inhibition mechanism of cysteine (Cys) and the effect of alloying elements were investigated by fitting experimental impedance data according to a projected equivalent circuit for the alloy/electrolyte interface. A Langmuir adsorption isotherm was proposed to explain the inhibition phenomenon of cysteine on the Cu-5Zn-5Al-1Sn alloy surface. Surface morphology observation confirmed that the Cu-5Zn-5Al-1Sn alloy was damaged in 3.5 wt.% NaCl solution and could be inhibited by using the cysteine inhibitor. The impact of alloying elements on the corrosion mechanism was further examined by surface analysis techniques such as X-Ray photoelectron spectroscopy (XPS)/Auger spectra, the results of which indicated that the corrosion inhibition was realized by the adsorption of the inhibitor molecules at the alloy/solution interface. Appl. Sci. 2019, 9, 3896 2 of 17 latter largely present at the outmost surface of both Cu and the Cu5Zn5Al1Sn alloy [7,11]. Although a big difference exists in their corrosion rates, the corrosion process is highly administered by the molecular diffusion between the metal surface and the electrolyte [12].One approach to prevent corrosion of Cu and its alloy is the use of corrosion inhibitors [13,14]. Among the corrosion inhibitors used in practice, cysteine (Cys) is found to be widely employed for Cu protection in various media [15,16]. Cysteine is an amino acid that contains a -SH group in addition to the amino group; this mercaptan group is strongly attracted to copper. A. A. Nazeer et al. have studied the inhibitive effect of cysteine on a Cu10Ni alloy in sulfide containing atmospheres [16]. Based on this study, cysteine can act as a mixed-type inhibitor and cysteine molecules are adsorbed on the alloy surface. The inhibition mechanism of cysteine with copper-based materials is characterized by the formation of a stable Cu (I)-cysteine complex [17]. As confirmed by many researchers, the better corrosion inhibition effect of cysteine relies on its surface adsorption through sulfur atoms [18,19]. I. Milošev et al. on the other hand have studied different amino acids as inhibitors for copper in acidic environments and confirmed that cysteine has higher efficiency. Based on their molecular dynamic simulation results, it has been suggested that the -SH group is in charge of the good protective effect of cysteine [20...

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“… Ultraviolet–visible absorption spectra (a) and corresponding bandgaps of SQDs (b). Figure 3 was reprinted from [ 46 ], Materials Letters, vol. 221, by Babu, B.; Neelakanta Reddy, I.; Yoo, K.; Kim, D.; Shim, J.…”

Section: Reviewmentioning

confidence: 99%

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

Pham¹,

Tran²,

Truong³

et al. 2022

Beilstein J. Nanotechnol.

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Semiconducting SnO2 photocatalyst nanomaterials are extensively used in energy and environmental research because of their outstanding physical and chemical properties. In recent years, nitrogen oxide (NOx) pollutants have received particular attention from the scientific community. The photocatalytic NOx oxidation will be an important contribution to mitigate climate change in the future. Existing review papers mainly focus on applying SnO2 materials for photocatalytic oxidation of pollutants in the water, while studies on the decomposition of gas pollutants are still being developed. In addition, previous studies have shown that the photocatalytic activity regarding NOx decomposition of SnO2 and other materials depends on many factors, such as physical structure and band energies, surface and defect states, and morphology. Recent studies have been focused on the modification of properties of SnO2 to increase the photocatalytic efficiency of SnO2, including bandgap engineering, defect regulation, surface engineering, heterojunction construction, and using co-catalysts, which will be thoroughly highlighted in this review.

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Bandgap tuning and XPS study of SnO2 quantum dots

Cited by 110 publications

References 15 publications

Highly Selective, ppb-Level Xylene Gas Detection by Sn2+-Doped NiO Flower-Like Microspheres Prepared by a One-Step Hydrothermal Method

Highly Selective, ppb-Level Xylene Gas Detection by Sn2+-Doped NiO Flower-Like Microspheres Prepared by a One-Step Hydrothermal Method

The Protection Role of Cysteine for Cu-5Zn-5Al-1Sn Alloy Corrosion in 3.5 wt.% NaCl Solution

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

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