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- 实验方案
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Charge transportation at cascade energy structure interfaces of CuInxGa1-xSeyS2-y/CdS/ZnS for spontaneous water splitting
摘要： A photoelectrode has to generate high enough photovoltage by efficient charge separation spontaneously to split water. In this study, cascade band structures with CdS and ZnS applied to CuInxGa1-xSeyS2-y (CIGS) photoelectrode of water splitting. The morphology, the electronic and the chemical state of CIGS heterojunction films have been characterized by a scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. The CIGS/CdS/ZnS photocathode shows ~400 mV anodic shift of onset potential and 0.028% efficiency for solar to hydrogen conversion when it couples with a WO3/BiVO4/Co-Pi photoanode for water splitting without external bias potential.
关键词： Photoelectrochemical cell,water splitting,CdS,CIGS,ZnS
更新于2025-09-23 15:21:21
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A novel growth control of nanoplates WO3 photoanodes with dual oxygen and tungsten vacancies for efficient photoelectrochemical water splitting performance
摘要： Recently, there has been attractive attention over the defect-engineering where the optimum extent of oxygen deficiency has been considered as an effective route towards enhancing the solar-driven water oxidation photocurrent. In this study, a nanoplate-like tungsten oxide with dual oxygen and tungsten vacancies (WO3-x) was successfully fabricated on tungsten foil by acid-mediated hydrothermal treatment to highly improve the photoelectrochemical (PEC) performance of WO3-x photoanode. Thermal annealing at 550 °C in air led to an oxygen deficient surface with a sub-stoichiometric by phase transformation from orthorhombic WO3·.nH2O to γ-monoclinic. However, the optimum number of oxygen vacancies in WO3-x fabricated at 2 h (W-2 h) with compact, porous and uniform nanoplate film that provide a large surface area for efficient charge collecting capability, caused an enhanced photocurrent density of 4.12 mA/cm2 (41.2 mA/W) at 1.6 V vs. Ag/AgCl, as compared to W-3 h (2.59 mA/cm2, or 25.9 mA/W) and W-30 min (1.79 mA/cm2 or 17.9 mA/W). Finally, local variations in dual oxygen and tungsten vacancies and in the electronic band structure of a WO3-x thin film was analyzed with ultraviolet photoelectron spectroscopy (UPS) and UV–visible diffuse reflectance spectroscopy (UV-DRS).
关键词： Photoelectrocatalytic,Water splitting,Growth control,Oxygen and tungsten vacancies,Nanoplates,WO3-X
更新于2025-09-23 15:21:21
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Highly Enhanced Photocatalytic Water-splitting Activity of Gallium Zinc Oxynitride Derived from Flux-assisted Zn/Ga Layered Double Hydroxides
摘要： The Ga/Zn-oxynitride solid solution [(GaN)1-x(ZnO)x] is one of the promising visible-light harvesting photocatalysts for overall water-splitting. A series of (GaN)1-x(ZnO)x (0.11 ≤ x ≤ 0.33) are synthesized by calcining the carbonate-type Zn/Ga-LDH precursor with and without sodium carbonate flux at 850 oC for 8 - 14 h under a NH3 gas-flow. The solid solutions without flux are determined to be low in crystallinity but plate-like in morphology with preferred orientation could be observed. On the other hand, those with flux turn out to be better in crystallinity, and eventually exhibit significantly higher photocatalytic activity for overall water splitting under visible-light irradiation than those without flux. In addition, the bandgap energies can also be engineered from 2.57 eV to 2.72 eV by changing the synthetic parameter such as nitridation time. It is, therefore, suggested that the present new approach can offer new opportunities for designing the next generation photocatalytic systems.
关键词： Overall water splitting,Photocatalyst,Gallium Zinc Oxynitride,Layered double hydroxides,Flux
更新于2025-09-23 15:21:21
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Disentangling Coupling Effects in the Infrared Spectra of Liquid Water
摘要： A quantitative characterization of intermolecular and intramolecular couplings that modulate the OH-stretch vibrational band in liquid water has so far remained elusive. Here, we take up this challenge by combining the centroid molecular dynamics (CMD) formalism, which accounts for nuclear quantum effects, with the MB-pol potential energy function, which accurately reproduces the properties of water across all phases, to model the infrared (IR) spectra of various isotopic water solutions with different levels of vibrational couplings, including those that cannot be probed experimentally. Analysis of the different IR OH-stretch lineshapes provides direct evidence for the partially quantum-mechanical nature of hydrogen bonds in liquid water, which is emphasized by synergistic effects associated with intermolecular coupling and many-body electrostatic interactions. Furthermore, we quantitatively demonstrate that intramolecular coupling, which results in Fermi resonances due to the mixing between HOH-bend overtones and OH-stretch fundamentals, are responsible for the shoulder located at ～3250 cm?1 of the IR OH-stretch band of liquid water.
关键词： liquid water,nuclear quantum effects,infrared spectra,Fermi resonances,centroid molecular dynamics,hydrogen bonds,intramolecular coupling,intermolecular coupling,MB-pol potential energy function
更新于2025-09-23 15:21:21
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ZnO/ZnO <sub/>2</sub> /Pt Janus Micromotors Propulsion Mode Changes with Size and Interface Structure: Enhanced Nitroaromatic Explosives Degradation under Visible Light
摘要： Self-motile mesoporous ZnO/Pt-based Janus micromotors accelerated by bubble propulsion that provide efficient removal of explosives and dye pollutants via photodegradation under visible light are presented. Decomposition of H2O2 (the fuel) is triggered by a platinum catalytic layer asymmetrically deposited on the nanosheets of the hierarchical and mesoporous ZnO microparticles. The size-dependent motion behavior of the mesoporous micromotors is studied; the micromotors with average size ～1.5 μm exhibit enhanced self-diffusiophoretic motion, whereas the fast bubble propulsion is detected for micromotors larger than 5 μm. The bubble-propelled mesoporous ZnO/Pt Janus micromotors show remarkable speeds of over 350 μm s?1 at H2O2 concentrations lower than 5 wt %, which is unusual for Janus micromotors based on dense materials such as ZnO. This high speed is related to efficient bubble nucleation, pinning, and growth due to the highly active and rough surface area of these micromotors, whereas the ZnO/Pt particles with a smooth surface and low surface area are motionless. We discovered new atomic interfaces of ZnO2 introduced into the ZnO/Pt micromotor system, as revealed by X-ray diffraction (XRD), which contribute to enhance their photocatalytic activity under visible light. Such coupling of the rapid movement with the high catalytic performance of ZnO/Pt Janus micromotors provides efficient removal of nitroaromatic explosives and dye pollutants from contaminated water under visible light without the need for UV irradiation. This paves the way for real-world environmental remediation efforts using microrobots.
关键词： mesoporous,bubble propulsion,diffusiophoresis,water purification,micromotors
更新于2025-09-23 15:21:21
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Handbook of Ecomaterials || Environmental Photocatalysis/Photocatalytic Decontamination
摘要： Water pollution caused by hazardous substances has become a global concern. Textile and dyestuff industries produce large amounts of wastewater containing various dye pollutants. Most azo dyes are nonbiodegradable and their release into the environment poses a major threat to the surrounding ecosystems. Remediation of organic aquatic pollutants by photocatalytic oxidation has proven to be an attractive promising technology among the advanced oxidation processes. Semiconductor photocatalysis is a topic of current interest mainly in view of its potential application in the mineralization of pollutants.
关键词： Pilot scale treatment,Heterogeneous photocatalysis,Air purification,Antimicrobial activity,Semiconductor oxides,Water pollution
更新于2025-09-23 15:21:21
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Multi-Spectral Water Index (MuWI): A Native 10-m Multi-Spectral Water Index for Accurate Water Mapping on Sentinel-2
摘要： Accurate water mapping depends largely on the water index. However, most previously widely-adopted water index methods are developed from 30-m resolution Landsat imagery, with low-albedo commission error (e.g., shadow misclassified as water) and threshold instability being identified as the primary issues. Besides, since the shortwave-infrared (SWIR) spectral band (band 11) on Sentinel-2 is 20 m spatial resolution, current SWIR-included water index methods usually produce water maps at 20 m resolution instead of the highest 10 m resolution of Sentinel-2 bands, which limits the ability of Sentinel-2 to detect surface water at finer scales. This study aims to develop a water index from Sentinel-2 that improves native resolution and accuracy of water mapping at the same time. Support Vector Machine (SVM) is used to exploit the 10-m spectral bands among Sentinel-2 bands of three resolutions (10-m; 20-m; 60-m). The new Multi-Spectral Water Index (MuWI), consisting of the complete version and the revised version (MuWI-C and MuWI-R), is designed as the combination of normalized differences for threshold stability. The proposed method is assessed on coincident Sentinel-2 and sub-meter images covering a variety of water types. When compared to previous water indexes, results show that both versions of MuWI enable to produce native 10-m resolution water maps with higher classification accuracies (p-value < 0.01). Commission and omission errors are also significantly reduced particularly in terms of shadow and sunglint. Consistent accuracy over complex water mapping scenarios is obtained by MuWI due to high threshold stability. Overall, the proposed MuWI method is applicable to accurate water mapping with improved spatial resolution and accuracy, which possibly facilitates water mapping and its related studies and applications on growing Sentinel-2 images.
关键词： MNDWI,OSH,SVM,AWEI,water mapping,water classification,shadow,NDWI,Sentinel-2,MuWI,Landsat,water index,multi-spectral water index,sunglint,machine learning
更新于2025-09-23 15:21:01
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Exploring Triple-isotopic Signatures of Water in Human Exhaled Breath, Gastric Fluid and Drinking Water Using Integrated Cavity Output Spectroscopy
摘要： Water, the major body fluid in humans, has four main naturally occurring isotopologues, H2 16O, H2 17O, H2 18O and H2H16O (i.e. HD16O) with different masses. The underlying mechanisms of the isotope-specific water-metabolism in human gastrointestinal (GI) tract and respiratory system are largely unknown and remained illusive for several decades. Here, a new strategy has been demonstrated that provides the direct quantitative experimental evidences of triple-isotopic signatures of water-metabolism in human body in response to the individual’s water intake habit. The distribution of water isotopes have been monitored in drinking water (DW) (δD =-36.59±10.64‰ (SD), δ18O= -5.41±1.47‰ (SD) and δ17O= -2.92±0.79‰ (SD)), GI fluid (GF) (δD =-35.91±7.30‰ (SD), δ18O= -3.98±1.29‰ (SD) and δ17O= -2.37±0.57‰ (SD)) and human exhaled breath (EB) (δD =-119.63±7.27‰ (SD), δ18O= -13.69±1.23‰ (SD) and δ17O= -8.77±0.98‰ (SD)) using the laser-based off-axis integrated cavity output spectroscopy (OA-ICOS) technique. This study explored a new analytical method to disentangle the competing effects of isotopic fractionations of water during respiration in humans. In addition, our findings revealed that deuterium-enriched exhaled semi-heavy water, i.e. HD16O is a new marker of the non-invasive assessment of the ulcer-causing H. pylori gastric pathogen. We also clearly showed that the water-metabolism-derived triple-isotopic compositions due to impaired water absorption in GI tract can be used as unique tracers to track the onset of various GI dysfunctions. These findings are thus bringing a new analytical methodology for better understanding the isotope-selective water-metabolism that will have enormous applications in clinical testing purpose.
关键词： triple-isotopic signatures,human exhaled breath,integrated cavity output spectroscopy,drinking water,water-metabolism,gastric fluid
更新于2025-09-23 15:21:01
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A Noble-Metal-Free Heterogeneous Photosensitizer-Relay-Catalyst Triad Catalyzes Water Oxidation under Visible Light
摘要： An entirely earth abundant chromophore-relay-water oxidation catalyst triad system, which is robust and efficient at neutral pH, is presented. The synthesis involves the coordination of a porphyrin derivative to a bridging Fe(CN)5 group, which is then reacted with Co ions to prepare a covalently linked chromophore-Prussian blue analogue assembly. Light driven water oxidation studies in the presence of an electron scavenger indicate that the triad is active and it maintains a steady activity for at least 3 hours. Transient absorption experiments and computational studies reveal that the Fe(CN)5 group is more than a linker as it takes part in electron-transfer and co-operates with porphyrin in the charge separation process.
关键词： water splitting,triad,dye-sensitized,water oxidation,Prussian blue,porphyrin
更新于2025-09-23 15:21:01
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Coupled retrieval of the three phases of water from spaceborne imaging spectroscopy measurements
摘要： Measurements of reflected solar radiation by imaging spectrometers can quantify water in different states (solid, liquid, gas) thanks to the discriminative absorption shapes. We developed a retrieval method to quantify the amount of water in each of the three states from spaceborne imaging spectroscopy data, such as those from the German EnMAP mission. The retrieval couples atmospheric radiative transfer simulations from the MODTRAN5 radiative transfer code to a surface reflectance model based on the Beer-Lambert law. The model is inverted on a per-pixel basis using a maximum likelihood estimation formalism. Based on a unique coupling of the canopy reflectance model HySimCaR and the EnMAP end-to-end simulation tool EeteS, we performed a sensitivity analysis by comparing the retrieved values with the simulation input leading to an R2 of 0.991 for water vapor and 0.965 for liquid water. Furthermore, we applied the algorithm to airborne AVIRIS-C data to demonstrate the ability to map snow/ice extent as well as to a CHRIS-PROBA dataset for which concurrent field measurements of canopy water content were available. The comparison between the retrievals and the ground measurements showed an overall R2 of 0.80 for multiple crop types and a remarkable clustering in the regression analysis indicating a dependency of the retrieved water content from the physical structure of the vegetation. In addition, the algorithm is able to produce smoother and more physically-plausible water vapor maps than the ones from the band ratio approaches used for multispectral data, since biases due to background reflectance are reduced. The demonstrated potential of imaging spectroscopy to provide accurate quantitative measures of water from space will be further exploited using upcoming spaceborne imaging spectroscopy missions like PRISMA or EnMAP.
关键词： Atmospheric correction,EnMAP,Canopy water content,Water vapor,Imaging spectroscopy
更新于2025-09-23 15:21:01