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Perspectives on the adsorption of CO2 on amine-modified silica studied by infrared spectroscopy
摘要： Amine-modified adsorbents are being researched for their potential to capture CO2 from various gas mixtures, and we review how IR spectroscopy has been used to study the associated CO2–amine chemistry. It has been used to reveal that CO2 chemisorbs as ammonium-carbamate ion pairs especially when the amine density is high. Carbamic acid and related other moieties tend to form in parallel to the ion pairs when the amine density is low. The amines have been shown to degrade on cyclic heat treatment. To further study the formation of bicarbonates on reactive adsorption of CO2 and H2O, degradation of the organics, and the use of other supports than silica are suggested.
关键词： porous materials,FT-IR spectroscopy,amine-modified silica,carbon capture,CO2 adsorption
更新于2025-09-23 15:21:01
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Adsorption for SO2 gas molecules on B, N, P and Al doped MoS2: the DFT study
摘要： In this paper, we investigated SO2 adsorption on B, N, P and Al doped MoS2, which band structure, density of states, charge transfer, etc by the density function theory (DFT) calculation. Results show that the SO2 prefer to be absorbed at the top of Mo atom of MoS2. It is found that SO2 is strongly adsorbed on Al-MoS2 with considerable adsorption energy of -1–-2.33eV, however, the best adsorption position is the top of Mo atom of Al-MoS2, which the biggest Ea is -2.33eV, the best charge is -0.343e and the shortest d is 1.763?. So these findings confirm that Al-MoS2 can be used to detect the presence of SO2 in the environment.
关键词： SO2 adsorption,MoS2,Al-MoS2,doped MoS2,DFT study
更新于2025-09-23 15:21:01
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Surface Photocatalytic Research of Fe -doped TiO2 (001) Based On the First-principles
摘要： In this paper,the first-principles based on density functional theory was used to study the Fe/TiO2(001) band gap width and adsorption energy of C6H6 molecules at different positions on the surface of the molecule with different doping methods and different Fe content. Calculation of the band structure and density of states of Fe-doped TiO2 nanoparticles shows that, the surface gap doping is more favorable than the substitution doping to reduce the band gap of TiO2,and when the doping concentration is 6.122%,the maximum reduction of the band gap width is 59.3% higher than that of pure TiO2.According to the comparement of adsorption energy, it works out that the benzene molecule is mainly about horizontal adsorption on the surface of TiO2(001).Within the scope of the study, with the increase of Fe doping concentration, The adsorption energy does not decrease as the band gap, when the Fe atoms doping concentration is 4.167%,the maximum increase of adsorption energy is 63.2%.
关键词： photocatalytic,Fe-doped TiO2,band gap,first-principles,adsorption energy
更新于2025-09-23 15:21:01
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Modifying the geometric and electronic structure of hexagonal boron nitride on Ir(111) by Cs adsorption and intercalation
摘要： Epitaxial hexagonal boron nitride on Ir(111) is significantly modified by adsorption and intercalation of alkali-metal atoms. Regarding geometry, intercalation lifts the two-dimensional layer from its substrate and reduces the characteristic corrugation imprinted by direct contact with the metal substrate. Moreover, the presence of charged species in close proximity to the hexagonal boron nitride (hBN) layer strongly shifts the electronic structure (valence bands and core levels). We used scanning tunneling microscopy, low-energy electron diffraction, x-ray photoelectron spectroscopy (XPS), and the x-ray standing wave technique to study changes in the atomic structure induced by Cs adsorption and intercalation. Depending on the preparation, the alkali-metal atoms can be found on top and underneath the hexagonal boron nitride in ordered and disordered arrangements. Adsorbed Cs does not change the morphology of hBN/Ir(111) significantly, whereas an intercalated layer of Cs decouples the two-dimensional sheet and irons out its corrugation. XPS and angle-resolved photoelectron spectroscopy reveal a shift of the electronic states to higher binding energies, which increases with increasing density of the adsorbed and intercalated Cs. In the densest phase, Cs both intercalates and adsorbs on hBN and shifts the electronic states of hexagonal boron nitride by 3.56 eV. As this shift is not sufficient to move the conduction band below the Fermi energy, the electronic band gap must be larger than 5.85 eV.
关键词： hexagonal boron nitride,Cs adsorption,electronic structure,geometric structure,intercalation
更新于2025-09-23 15:21:01
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Metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid and its fluorescent sensing of fatty alcohol with different branch chains
摘要： This work reports the metal organic frameworks composite Eu2O3@[Zn2(1,4-ndc)2dabco] synthesized by pulsed laser ablation in flowing liquid. Powder X-ray Diffraction (PXRD) and SEM were used to characterize its structure and morphology. The results show that the Eu2O3 nanoparticles with the average particle size of 3.08 nm are uniformly distributed among the crystal and the BET specific surface area of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 1087 m2/g. At 296 K, the adsorption capacities of C2H2 on composite are up to 117.3 cm3/g, which is larger than that of the compound [Zn2(1,4-ndc)2dabco]. The C2H6/CH4 selectivity of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] is 25.9 and much higher than that of some familiar MOFs materials. Moreover, the composite Eu2O3@[Zn2(1,4-ndc)2dabco] can emit very intense characteristic fluorescence at 613 nm of Eu3t ion under ultraviolet radiation and can be used for detecting of fatty alcohols with different branch chains in fluorescence sensing because of its fluorescence intensity at 613 nm is sensitive to fatty alcohol with different carbon chains. The luminescence based sensing mechanism of the composite Eu2O3@[Zn2(1,4-ndc)2dabco] was discussed.
关键词： Flowing liquid,MOFs composites,Adsorption,Fatty alcohol with different branch chains,Pulsed laser ablation,Fluorescent sensing
更新于2025-09-23 15:19:57
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Cu-BTC assisted DSSCs with improved photovoltaic performances
摘要： MOF based composite material is adopted to modify photoanode, and the obtained large BET area is found meaningful to the dye loading amount, which brings about a high short circuit current and incident photon to current conversion efficiency. Meanwhile, three-dimensional graphene networks (3DGNs) is employed to provide a fast transport channel for photo-induced electrons. The morphology is analyzed by SEM, TEM, XRD and Raman spectrum, and the photovoltaic performances are recorded to reveal the specific functions of MOF and 3DGNs. The synergy between MOF, 3DGNs and TiO2 is achieved by adjusting their mass fraction. Moreover, the average size of MOF exerts a significant influence on the resulting properties resulting from the scattering ability to incident light. After corresponding optimizing, the short circuit current, open circuit voltaic, fill factor and energy conversion efficiency reach 20.5 mAcm-2, 680 mV, 0.619 and 8.63%.
关键词： Cu-BTC,dye adsorption ability,three-dimensional graphene networks,DSSCs
更新于2025-09-23 15:19:57
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The time response of plasmonic sensors due to binary adsorption: analytical versus numerical modeling
摘要： In order to allow for multiscale modeling of complex systems, we focus on various approaches to modeling binary adsorption. We consider multiple methods of modeling the temporal response of general plasmonic sensors. We start from the analytical approach. The kinetics of adsorption and desorption is modeled both as a first order reaction and as a second-order reaction. The criteria for their validity and the choice between them in the case of two-component adsorption are established. Due to the nonlinearities of the second-order reactions and the lack of their analytical solutions, computer-aided modeling is considered next, also in multiple ways: the employment of numerical solvers, fitting of experimental results, the stochastic simulation algorithms and the employment of artificial neural networks (ANN). The examples we present illustrate the advantages and disadvantages of the particular approaches. The goal is to aid the concurrent multiscale modeling of adsorption-based devices. Machine learning in ANN performed here is used to estimate the equilibrium values of adsorbed quantities. The obtained results show that to train an ANN for the estimation of the equilibrium adsorption quantities the Levenberg–Marquardt and the Bayesian regularization algorithms are less efficient than the quasi-Newton BFGS (Broyden–Fletcher–Goldfarb–Shanno) algorithm.
关键词： Kinetics,Stochastic simulation algorithms,Adsorption,Machine learning algorithms,Plasmonic sensing
更新于2025-09-23 15:19:57
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Green Synthesis of Highly Fluorescent Graphene Oxide/Carbon Quantum Dot Colloid from Rice
摘要： Carbon quantum dot–graphene oxide hybrids have been synthesized from rice precursor using a ball-milling-assisted hydrothermal method. The structure of the quantum dots and graphene oxide was studied using x-ray diffraction analysis, energy-dispersive x-ray spectroscopy, and elemental mapping. The size and morphology of the nanostructures were studied using ?eld-emission scanning electron microscopy and transmission electron microscopy, revealing that the product was composed of spherical nanoparticles and nanosheets. We argue that the presence of some metals in the rice precursor can catalyze the synthesis of graphene oxide. The structure of the product was studied by Fourier-transform infrared spectroscopy. Investigation of the optical properties of the quantum dots and graphene oxide by ultraviolet–visible spectroscopy and photoluminescence (PL) spectroscopy revealed strong PL properties. The PL quantum yield could be improved by surface modi?cation using polyethylene glycol, polyvinylpyrrolidone, ethylenediaminetetraacetic acid, and acetylacetone. The photocatalytic properties of the carbon nanomaterial (CNM) were investigated based on the decomposition of Eriochrome Black-T and Eosin Y dyes, revealing strong photocatalytic activity. The thermal stability of the product was examined by thermogravimetric analysis. Furthermore, atomic absorption spectroscopy showed that CNM could be used to eliminate cations of heavy metals such as lead and cadmium from toxic water.
关键词： Carbon quantum dots,photocatalyst,graphene oxide,photoluminescence,rice,surface adsorption
更新于2025-09-23 15:19:57
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Porphyrin dyes bearing heterocyclic anchoring groups for dye-sensitized solar cells with enhanced efficiency and long-term stability: further optimization of champion porphyrin dye SM315
摘要： In order to further enhance the long-term stability of porphyrin-based dye-sensitized solar cells (DSSCs) without losing their high efficiency, a serious of porphyrin sensitizers based on the champion dye SM315 but differing in the anchoring groups were theoretically investigated. Compared with SM315 with carboxylic acid anchoring groups, our results demonstrate that porphyrin dyes with hydantoin and barbituric acid anchoring groups exhibit stronger adsorption stability because of the larger orbital interactions between the dye and the semiconductor surface, according to the energy decomposition analysis. Furthermore, porphyrin dyes with these two heterocyclic anchoring groups can also display a superior or comparable charge separation and injection, light harvesting ability and conduction band energy shift, which are the key factors that affect the performance of DSSCs. These results highlight the great potential hydantoin and barbituric acid anchoring groups possess as effective alternatives to carboxylic acid anchoring groups for porphyrin dyes, which could yield an enhanced efficiency and long-term stability and worthy of being experimentally synthesized.
关键词： Adsorption stability,Porphyrin,Heterocyclic anchoring groups,Dye-sensitized solar cells,Theoretical study
更新于2025-09-23 15:19:57
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Carbon Nanomaterials for Agri-Food and Environmental Applications || Graphene quantum dot-based nanostructures for water treatment
摘要： Water pollution by organic, inorganic, and microbial species presents a threat to the water supply as well as food safety and security. Graphene quantum dot-derived nanostructures have emerged as potential solutions toward water pollution mitigation. Such materials have been successfully prepared and evaluated for the catalytic removal of organic pollutants such as dyes and emerging pollutants, the adsorption of pollutants, filtration, and disinfection. Incorporation of GQDs in various nanocomposites resulted in the modification of the composite properties and improved the removal efficiencies of different pollutants. Careful control and optimization of the amounts of GQDs incorporated are necessary to ensure a positive influence in the pollutant-removal efficiencies of the different nanocomposites. Despite the promising developments around GQD-based nanostructures, more work still remains in order to ensure the design and utilization of such materials in large-scale applications. Nonetheless, GQD-derived nanostructures have potential as pollution remediation tools, owing to the nontoxicity, biodegradable, and abundant functional groups. However, there is a need to develop optimized synthesis conditions that will yield GQDs that are uniform in terms of size and surface functionalities and also develop synthesis routes that will ensure proper distribution of the GQDs within the nanocomposite matrix. This could contribute to consistency in terms of the reported performances of various GQD-derived nanostructures in water pollution abatement.
关键词： membrane filtration,photocatalysis,Graphene quantum dots,water treatment,adsorption
更新于2025-09-23 15:19:57