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Zinc ions modified InP quantum dots for enhanced photocatalytic hydrogen evolution from hydrogen sulfide
摘要： Through direct addition of inorganic zinc ions into the solution of indium phosphide quantum dots (InP QDs) at ambient environment, we here present a facile but effective method to modify InP QDs for photocatalytic hydrogen evolution from hydrogen sulfide (H2S). X-ray diffraction patterns and transmission electron microscopic images demonstrate that zinc ions have no significant influence on the crystal structure and morphology of InP QDs, while X-ray photoemission spectra and UV–Vis diffuse and reflectance spectra indicate that zinc ions mainly adsorbed on the surface of InP QDs. Photocatalytic results show the average hydrogen evolution rate has been enhanced to 2.9 times after modification and H2S has indeed involves in the hydrogen evolution process. Steady-state and transient photoluminescence spectra prove that zinc ions could effectively eliminate the surface traps on InP QDs, which is crucial to suppress the recombination of charge carriers. In addition, the electrostatic interaction between zinc ions and the surface sulfide from InP QDs could mitigate the repulsion between QDs and sulfide/hydrosulfide, which may promote the surface oxidative reaction during photocatalysis. This work avoids the traditional harsh and complicated operations required for surface passivation of QDs, which offers a convenient way for optimization of QDs in photocatalysis.
关键词： Hydrogen sulfide,Photocatalytic hydrogen evolution,InP quantum dots,Surface modification
更新于2025-10-22 19:38:57
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Z-Scheme 2D/2D Heterojunction of Black Phosphorus/Monolayer Bi2WO6 Nanosheets with Enhanced Photocatalytic Activities
摘要： Black phosphorus (BP), a star-shaped two-dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Herein, we design and fabricate a Z-Scheme heterojunction of 2D/2D BP/monolayer Bi2WO6 (MBWO) by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g-1, is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67%. A Z-Scheme photocatalytic mechanism is proposed based on monitoring of ?O2?, ?OH, NO2, and NO3? species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
关键词： hydrogen production,photocatalytic,Black phosphorus,2D/2D heterojunction,Z-Scheme
更新于2025-09-23 15:23:52
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A heterobimetallic Au(III)?Pt(II) photocatalyst for water reduction to hydrogen
摘要： A supramolecular complex, [Au(C^N^C)(C≡CC6H4C≡C)Pt(terpy)]+, has been synthesized as a photocatalyst for water reduction. This compound consists of a cyclometalated alkyngold(III) photosensitizer and a platinum(II) terpyridine complex bridged through a central phenylethynyl group.
关键词： heterobimetallic system,hydrogen evolution,photocatalyst
更新于2025-09-23 15:23:52
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Theoretical elaboration about the excited state dynamical behaviors for a novel fluorescent sensor
摘要： Using the density functional theory (DFT) and time‐dependent density functional theory (TDDFT) methods, we theoretically explore a novel fluorescent sensor molecule (abbreviated as “2”) (Sensors Actuat B‐Chem. 2018, 263, 585). Because of its symmetry, three stable structures can be located, ie, 2‐enol, 2‐SPT, and 2‐DPT forms in both S0 and S1 states. Via comparing the bond lengths and bond angles involved in the hydrogen bonding moieties, we find the dual intramolecular hydrogen bonds should be strengthened in the S1 state. And based on infrared (IR) vibrational simulations, we further confirm the strengthening dual hydrogen bonds. Upon the photo‐excitation process, the charge redistribution via frontier molecular orbitals (MOs) reveals the tendency of excited state intramolecular proton transfer (ESIPT) reaction. In addition, the constructed S0‐state and S1‐state potential energy curves demonstrate that the excited state single proton transfer (ESSPT) should be the most supported one from 2‐enol to 2‐SPT form. In view of the S1‐state stable 2‐SPT and 2‐DPT structures as well as the fluorescence peaks of them, we can further confirm the ESSPT mechanism for 2 chemosensor. This work not only clarifies the excited state behaviors of 2 system but also successfully explain the previous experimental phenomenon.
关键词： charge redistribution,ESIPT,potential energy curves,intramolecular hydrogen bond
更新于2025-09-23 15:23:52
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The Influence of Ceramic Far-Infrared Ray (cFIR) Irradiation on Water Hydrogen Bonding and its Related Chemo-physical Properties
摘要： The property of water is highly related to the earth's environment and climate change. The fundamental dynamical process of water is include formation and breaking of hydrogen bonds. This dynamic process, so far, is still poorly understood. We investigated weakening of the hydrogen bonds of water after ceramic Far-Infrared Ray (cFIR) irradiation and the resulting effects on physical and chemical properties of water. In this study, the Fourier transform infrared spectroscopy (FT-IR) was used to explore hydrogen bonding change of cFIR-irradiated water; in addition, capillary viscometers, Gas Chromatographs (GC), Differential Scanning Calorimetry (DSC), contact angles, Franz cells, High-Performance Liquid Chromatography (HPLC), and capillary electrophoresis analysis were used to evaluate its physical characteristics, such as viscosity, volatility, temperatures of water crystallization, surface tension, diffusion, hydrogen peroxide dissociation, solubility of solid particles, and changes in pH of acetic acid. The cFIR treated water decreased in viscosity and surface tension (contact angles), but increased in the solubility of solid particles, hydrogen peroxide dissociation, temperatures of water crystallization, and acidity of acetic acid. The weakening of water hydrogen bonds caused by cFIR irradiation is correspondent with our previous medical-biological studies on cFIR.
关键词： Hydrogen bonds,Fourier transform infrared spectroscopy (FT-IR),Contact angle,Ceramic far infrared ray (cFIR),Irradiation water,Solubility,Volatility
更新于2025-09-23 15:23:52
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Construction of a Biosensor Based on a Combination of Cytochrome c, Graphene, and Gold Nanoparticles
摘要： A biosensor based on a combination of cytochrome c (Cyt c), electrochemical reduced graphene oxides (ERGO), and gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) was fabricated. The proposed biosensor electrode was denoted as GCE/ERGO-Na?on/AuNPs/Cyt c/Na?on, where ERGO-Na?on was deposited by dropping graphene oxides-Na?on mixed droplet ?rst and following electrochemical reduction, AuNPs were directly deposited on the surface of the ERGO-Na?on modi?ed electrode by electrochemical reduction, and other components were deposited by the dropping-dry method. The effect of the deposition amount of AuNPs on direct electrochemistry of Cyt c in the proposed electrode was investigated. The hydrogen peroxide was taken to evaluate the performance of the proposed biosensor. The results showed that the biosensor has great analytical performance, including a high sensitivity, a wide linear range, a low detection limit, and good stability, reproducibility, and reliability.
关键词： gold nanoparticles,cytochrome c,graphene,direct electrochemistry,biosensor,hydrogen peroxide
更新于2025-09-23 15:23:52
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2D-montmorillonite-dispersed g-C3N4/TiO2 2D/0Dnanocomposite for enhanced photo-induced H2 evolution from glycerol-water mixture
摘要： Montmorillonite (MMT) dispersed g-C3N4/TiO2 hybrid nanocomposite for enhanced photo-catalytic hydrogen production from glycerol-water mixture has been investigated. The newly designed composite photo-catalysts were fabricated through a sol-gel assisted hydrothermal method and were characterized by XRD, XPS, SEM, EDX, TEM, FTIR, UV–Vis, Raman and PL spectroscopy. Well-designed g-C3N4/MMT/TiO2 heterojunction composite was obtained with 2D MMT structure, which promoted both visible light absorption and hindered charges recombination rate. The modification of 2D/0D g-C3N4/TiO2 heterojunction with 2D MMT sheets enhances H2 production due to MMT works as a mediator for effective charges trapping and transportation within the composite structure. The g-C3N4/MMT/TiO2 photo-catalyst exhibits highest H2 production of 4425 ppm h?1 g?1 at pH 7.0, which was 2.12 times higher than the pure TiO2 (2085 ppm h?1 g?1). In addition, increasing catalyst loading promotes more H2 evolution and among the different sacrificial reagents, glycerol-water mixture gave highest H2 production due to the presence of α-hydrogen atoms attached to carbon atoms. The enhanced photocatalytic efficiency can be attributed to synergistic effect of MMT with g-C3N4/TiO2 heterojunction composite, appropriate band structure and transportation of electrons–holes with their hindered recombination rate. These composite catalysts exhibited excellent photo-catalytic stability for H2 production in cyclic runs. Possible reaction mechanism for hydrogen production over g-C3N4/MMT/TiO2 composite has been explained based on the experimental results. The finding of this work would be fruitful for hydrogen production applications with all sustainable systems.
关键词： TiO2,Photo-catalysis,Montmorillonite,g-C3N4,Z-scheme,Hydrogen production
更新于2025-09-23 15:23:52
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Hydrogen reduction characteristics of WO3 based on density functional theory
摘要： The ?rst principle theory in DFT (Density Function Theory) was applied to study the hydrogen adsorption on O-terminated and WO-terminated surface of WO3 (0 0 1). The exploration of the two terminated surfaces structure and hydrogen adsorption characteristics was conducted from the micro-structure point of view. The result indicates that energy of O-terminated surface with enriched oxygen is higher than the WO-terminated surface with less oxygen. The chemical adsorption occurs when the distance between hydrogen molecules and surface atom ranged from 0.6 ? to 0.8 ?, while the physical adsorption occurs when the distance was bigger than 0.8 ?. The energy of hydrogen adsorption on O-terminated surface is lower than energy of hydrogen adsorption on WO-terminated surface, the chemical adsorption of hydrogen is easier to happen compare to physical adsorption. The energy of hydrogen adsorption on O1c on O-terminated surface is lower than energy of hydrogen adsorption on O2c on the same surface. The adsorption of hydrogen not only changes the structure of surfaces of WO3 and cause the conducting electrons jumping into valence band and energy declining but also make a part of electrons in orbit 2p of O to jump into orbit 5p of W.
关键词： Hydrogen adsorption,First principle,Density of states,Reduction,WO3
更新于2025-09-23 15:23:52
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Enzymatic sensor for phenols based on titanium dioxide generating surface confined ROS after treatment with H2O2
摘要： Titanium dioxide (TiO2) is a popular material as host matrix for enzymes. We now evidence that TiO2 can accumulate and retain reactive oxygen species after treatment by hydrogen peroxide (H2O2) and support redox cycling of a phenolic analyte between horseradish peroxidase (HRP) and an electrode. The proposed detection scheme is identical to that of second generation biosensors, but the measuring solution requires no dissolved H2O2. This significantly simplifies the analysis and overcomes issues related to H2O2 being present (or generated) in the solution. The modified electrodes showed rapid stabilization of the baseline, a low noise level, fast realization of a steady-state current response, and, in addition, improved sensitivity and limit of detection compared to the conventional approach, i.e. in the presence of H2O2 in the measuring solution. Hydroquinone, 4-aminophenol, and other phenolic compounds were successfully detected at sub-μM concentrations. Particularly, a linear response in the concentration range between 0.025 and 2 μM and LOD of 24 nM was demonstrated for 4-aminophenol. The proposed sensor design goes beyond the traditional concept with three sensors' generations offering a new possibility for the development of enzymatic sensors based on peroxidases and the formation of ROS on titania after treatment with H2O2.
关键词： Hydroperoxyl species,Titanium dioxide,Horseradish peroxidase,Bioelectrochemistry,Hydrogen peroxide
更新于2025-09-23 15:23:52
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H2 production by the water splitting reaction using photocatalysts derived from calcined ZnAl LDH
摘要： Photocatalysts based on calcined ZnAl layered double hydroxides were obtained by coprecipitation and the subsequent thermal treatments at different temperatures. The calcined materials were characterized and its photocatalytic behavior was evaluated in the water splitting reaction in presence of UV irradiation. According to the XRD analysis, there was detected the presence of Zn as hexagonal ZnO in all the samples, as well as Al forming ZnAl2O4 and Zn6Al2O9, depending on the temperature of calcination employed. H2 yield was higher as the annealing temperature was increased due to the formation of the heterojunctions of ZnO with the Zn6Al2O9 and ZnAl2O4 oxides, reaching the maximum value in the sample annealed at 600 °C. Some decay in the activity was observed in the sample calcined at 700 °C, probably due to the higher recombination rate of the photo-generated charge carriers in that heterojunction in comparison with that obtained at 600 °C.
关键词： Hydrogen,Calcined LDH,ZnAl mixed oxides,Photocatalyst,Heterojunction,Water splitting
更新于2025-09-23 15:23:52