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Tris(N-methylferrocenyl-N-(2-phenylethyl)dithiocarbamato-S,S′)cobalt(III) for anion sensing and preparation of cobalt-iron sulfide nanoparticles: A new photocatalyst for the degradation of dyes
摘要： Tris(N-(pyrrol-2-ylmethyl)-N-butyldithiocarbamato-S,S')cobalt(III) (1) and tris(N-methylferrocenyl-N-(2-phenylethyl)dithiocarbamato-S,S')cobalt(III) (2) have been synthesized and characterized by elemental analysis and spectroscopy (IR, UV-vis and NMR). The elemental analysis and IR, 1H and 13C NMR spectra are consistent with the formation of the cobalt(III) complexes with dithiocarbamate ligands. The anion binding properties of 1 and 2 based on host-guest interaction have been examined with the use of cyclic voltammetry.This study showed that both complexes preferred to bind with I- compared to other halides. 2 has been used as precursors for the preparation of cobalt-iron sulfide nanoparticles. TEM image of cobalt-iron sulfide nanoparticles showed that the particles are spherical. The elemental compositions of the nanoparticles were confirmed by energy dispersive X-ray spectroscopy. IR spectral studies on nanoparticles confirm the presence of capping agent (triethylenetetramine). The nanoparticles were explored as photocatalysts to study the degradation of dyes using methylene blue and rhodamine-B in aqueous solution under UV irradiation. The cobalt-iron sulfide works as an efficient photocatalyst for degradation of rhodamine-B.
关键词： cobalt(III) dithiocarbamate,Anion sensing,single source precursors,nanoparticles,cobalt-iron sulfide
更新于2025-09-23 15:23:52
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Sub-ppm level NO2 sensing properties of polyethyleneimine-mediated WO3 nanoparticles synthesized by a one-pot hydrothermal method
摘要： A novel sensing material of polyethyleneimine-mediated WO3 nanoparticles was prepared by a simple and efficient one-pot hydrothermal method. The structure and morphology characteristics of the as-prepared WO3 nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The results showed that the as-prepared WO3 nanomaterials were composed of highly dispersible WO3 nanoparticles, and these nanoparticles with the particle size in the range of 10e50 nm showed a monoclinic structure. NO2 sensing measurements demonstrated that WO3 nanoparticles-based gas sensor exhibited superior response, outstanding selectivity, excellent reversibility, and good long-term stability. The sensor response increased as NO2 concentration increased. The highest response value of 251.7 was achieved to 5 ppm NO2 at the optimal operating temperature of 100 (cid:1)C. Especially, the sensor response could reach 3.2e50 ppb NO2. It also exhibited fast response and recovery times with a high sensor response even in a high-humidity environment. The excellent gas sensing properties of WO3 nanoparticles could be ascribed to their high effective surface areas as well as numerous oxygen vacancies, which foresee the great potential application for fast and effective detection of sub-ppm level NO2 under different humidity environments.
关键词： Nanoparticles,NO2,Gas sensing performance,WO3,Hydrothermal
更新于2025-09-23 15:23:52
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2D ultra-thin WO3 nanosheets with dominant {002} crystal facets for high-performance xylene sensing and methyl orange photocatalytic degradation
摘要： Here we report the synthesis of two-dimensional (2D) ultra-thin WO3 nanosheets (~4.9 nm) with dominant {002} crystal facets through a facile surfactant-induced self-assembly method. It was found that the ultra-thin WO3 nanosheets showed remarkably enhanced xylene sensing performance and methyl orange photocatalytic degradation performance, which could be ascribed to the high percentage of reactive {002} crystal facets (>90%) and high specific surface area (121 m2/g). The mechanism of gas sensing and photocatalysis was systematically studied. This work will be intriguing for designing high-performance metal oxides-based gas sensing and photocatalytic materials through 2D structural modulation and crystal facets engineering, which is important to promote their practical applications in environmental issues.
关键词： {002} crystal facets,2D,Photocatalysis,WO3,Gas sensing
更新于2025-09-23 15:23:52
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Multichannel luminescence properties and ultrahigh-sensitive optical temperature sensing of mixed-valent Eu2+/Eu3+ co-activated Ca8ZrMg(PO4)6(SiO4) phosphors
摘要： A novel dual-emitting Ca8ZrMg(PO4)6(SiO4): (Eu3+, Eu2+) phosphors with ultrahigh-sensitive optical temperature sensing are prepared by a conventional solid-state method. The Eu2+/Eu3+ co-activated Ca8ZrMg(PO4)6(SiO4) phosphors exhibit efficient dual-mode emissions with an intense, broad blue emission peaked at 414 nm and a relative bright red-emitting centered at 614 nm under 297 nm UV-light excitation, respectively. Furthermore, the fluorescence intensity ratio (FIR) technology is applied to analyze the optical temperature sensing performance of Ca8ZrMg(PO4)6(SiO4): (Eu3+, Eu2+) phosphors. Based on different thermal quenching behavior of Eu2+ and Eu3+ dual-emitting centers, linear temperature-dependent FIR between Eu2+ and Eu3+ is obtained. The maximal absolute sensitivity reaches as high as 5.94% K-1, which is superior to that for the other luminescent temperature sensing materials reported previously. Analyses of the temperature-dependent photoluminescence spectra and configurational coordinate diagrams for Ca8ZrMg(PO4)6(SiO4): (Eu3+, Eu2+) phosphors indicate that the temperature-sensitive variation in FIR of Eu2+ to Eu3+ is originated from the difference in thermal quenching activation energy for 5d→4f transition of Eu2+ and 5D0→7FJ (J=1, 2, 4) transitions of Eu3+. These results reveal that the Ca8ZrMg(PO4)6(SiO4): (Eu3+, Eu2+) phosphors show glorious potential in high temperature optical thermometry.
关键词： Co-activated,Ca8ZrMg(PO4)6(SiO4),Optical temperature sensing,FIR
更新于2025-09-23 15:23:52
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Facile synthesis of hierarchically nanostructured bismuth vanadate: An efficient photocatalyst for degradation and detection of hexavalent chromium
摘要： Heterostructured nanomaterials can paid more significant attention in environmental safety for the detection and degradation/removal of hazardous toxic chemicals over a decay. Here, we report the preparation of hierarchically nanostructured shuriken like bismuth vanadate (BiVO4) as a bifunctional catalyst for photocatalytic degradation and electrochemical detection of highly toxic hexavalent chromium (Cr(VI)) using the green deep eutectic solvent reline, which allows morphology control in one of the less energy-intensive routes. The SEM results showed a good dispersion of BiVO4 catalyst and the HR-TEM revealed an average particle size of ca. 5–10 nm. As a result, the BiVO4 exhibited good photocatalytic activity under UV-light about 95% reduction of Cr(VI) to Cr(III) was observed in 160 min. The recyclability of BiVO4 catalyst exhibited an appreciable reusability and stability of the catalyst towards the photocatalytic reduction of Cr(VI). Also, the BiVO4-modified screen printed carbon electrode (BiVO4/SPCE) displayed an excellent electrochemical performance towards the electrochemical detection of Cr(VI). Besides, the BiVO4/SPCE demonstrated tremendous electrocatalytic activity, lower linear range (0.01–264.5 μM), detection limit (0.0035 μM) and good storage stability towards the detection of Cr(VI). Importantly, the BiVO4 modified electrode was also found to be a good recovery in water samples for practical applications.
关键词： Shuriken-shaped BiVO4,Durable bifunctional catalyst,Deep eutectic green solvents,Photocatalytic Cr(VI) reduction,Electrochemical sensing
更新于2025-09-23 15:23:52
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Photophysical performance of a rhodamine-MOF composite structure and its sensing potential for picric acid
摘要： For the following paper, a rhodamine-MOF composite structure, RO-EuBTC, was constructed for the optical recognition of PA (picric acid) by the covalent combination of an organic rhodamine dye and rare earth MOF. By means of XRD, IR, TGA, this composite structure was analyzed and confirmed. Its photophysical analysis suggested two sensing aspects towards PA. Be more specific, RO-EuBTC's rhodamine absorption intensity in visible region was proportional to PA, showing colorimetric sensing. RO-EuBTC's rhodamine emission intensity was proportional to PA as well, with its Eu emission intensity inversely proportional to PA, showing self-calibrated sensing signals. Both sensing aspects showed linear response and high selectivity towards PA. Their LOD value was as low as 2.2 μM. Detailed analysis confirmed its sensing mechanism as the combination of two parts, namely the rhodamine emission enhancement sparked by PA's proton and the Eu emission quenching caused by EuBTC's electron transfer to PA. RO-EuBTC was found superior to traditional optical sensing materials based on MOFs owing to its two sensing aspects and the possibility for naked eye detection.
关键词： Self-calibrated signals,Emission increase and decrease,Dynamic sensing,Composite structure
更新于2025-09-23 15:23:52
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Remote Sensing Image Registration based on Phase Congruency Feature Detection and Spatial Constraint Matching
摘要： In this paper, a novel remote sensing image registration method based on phase congruency (PC) and spatial constraint is proposed. PC can provide intrinsic and meaningful image features, even when there are complex intensity changes or noise. Image features will be well detected from the corresponding PC images by the SAR-SIFT operator. It means that the feature detection methods in the frequency domain (PC) and the spatial domain (SAR-SIFT operator) are combined. To further improve the result of registration, spatial constraints, including point and line constraint, are established by utilizing the position and orientation information. Then, one to more matches can be removed and the influence of adjacent point can be greatly eliminated. The experimental results demonstrate that our method can obtain a better registration performance with higher accuracy and more correct correspondences than the state-of-the-art methods, such as SIFT, SAR-SIFT, SURF, PSO-SIFT, RIFT, and GLPM.
关键词： remote sensing,spatial constraint,SAR-SIFT operator,image registration,Phase congruency
更新于2025-09-23 15:23:52
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Remote Heart Rate Measurement from RGB-NIR Video Based on Spatial and Spectral Face Patch Selection
摘要： In this paper, we propose a novel heart rate (HR) estimation method using simultaneously recorded RGB and near-infrared (NIR) face videos. The key idea of our method is to automatically select suitable face patches for HR estimation in both spatial and spectral domains. The spatial and spectral face patch selection enables us to robustly estimate HR under various situations, including scenes under which existing RGB camera-based methods fail to accurately estimate HR. For a challenging scene in low light and with light fluctuations, our method can successfully estimate HR for all 20 subjects (±3 beats per minute), while the RGB camera-based methods succeed only for 25% of the subjects.
关键词： spectral domain,remote sensing,spatial domain,face patch selection,heart rate estimation,RGB-NIR video
更新于2025-09-23 15:23:52
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[IEEE 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Coimbatore (2018.3.29-2018.3.31)] 2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA) - Image Reconstruction Through Compressed Sensing Technique Using Gaussian Filteration
摘要： Image Processing is becoming as the one of the most emerging field in the research area, as we know in today's life, lot of people are using these images somewhere in their daily life. In this paper, i have developed the satellite images in which we can have even more clear view than the input taken image by using compressive reconstruction technique. After passing through some stages of the processing, we have used a gaussian filteration so that we can have a very good output image at an end. By taking various references through different sites I got a hope of developing a normal satellite taken image into clearly processed output image through the basis pursuit reconstruction and by doing filteration after it.
关键词： gaussian filter,compressed sensing,gaussian matrix,basis pursuit
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Investigating the Relationship Between Shallow Groundwater, Soil Moisture and Land Surface Temperature Using Remotely Sensed Data
摘要： Shallow groundwater has a decisive impact on land surface temperature (LST) and soil moisture (SM). In the present paper relationship between shallow groundwater, SM and LST was studied. For this purpose, the groundwater level and soil moisture were measured in 59 and 39 locations respectively in the southwest of Iran, during June 2016, Simultaneous with the overpass of a Landsat 8 satellite from the study site. After necessary image processing the LST was retrieved from the Landsat image using the split window algorithm. Then relationship between retrieved LST and different field observation were studied. Results show that there is a significant relationship between the groundwater depth and SM with LST. These results indicate that shallow groundwater depth and soil moisture content could be estimated and mapped using the retrieved LST from the satellite imagery.
关键词： Remote Sensing,LST,Landsat 8,Shallow Groundwater,Soil moisture
更新于2025-09-23 15:23:52