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Ellipsometric study on optical properties of hydrogen plasma-treated aluminum-doped ZnO thin film
摘要： Aluminum-doped zinc oxide (AZO) thin films were prepared by radio frequency (RF) sputtering at room temperature, and then post-treated by hydrogen (H2) plasma at different durations. After H2 plasma treatment under the condition of 10 W, 200 °C and 3.0 Hours, the resistivity showed a dramatically decrease from 1.6 Ω cm to 3.4 × 10?3 Ω cm, while the transmittance at the wavelength of 550 nm was improved from 90.5% to 96.0%. The optical constants of H2 plasma-treated AZO thin films were detailed characterized by a varied angle spectroscopic ellipsometer. The results show that the refractive index n decreases in the entire measured wavelength range of 350–1100 nm, while the extinction coefficient k decreases in the short wavelength range and changes negligibly at the long wavelength range. These results can provide guidelines for the design and optimization of AZO thin film-based optoelectronic applications.
关键词： Resistivity,Spectroscopic ellipsometer,Transmittance,Optical constants,Hydrogen plasma treatment,Aluminum-doped zinc oxide
更新于2025-11-14 17:03:37
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Excellent catalysis of TiO2 nanosheets with high-surface-energy {001} facets on hydrogen storage properties of MgH2
摘要： Transition metal compound is one of the highly efficient catalysts in improving the reaction kinetics of hydrogen storage materials. Among all the transition metal, titanium and its compounds show great catalytic effect on magnesium hydride. In this paper, TiO2 nanosheets with exposed {001} facets were synthesized and doped into MgH2 for the first time. The TiO2 nanosheets (NS) doped MgH2 shows superior kinetic performance and lowest desorption temperature. The onset temperature of MgH2 + 5 wt% TiO2 NS to release hydrogen is 180.5 °C and the corresponding peak temperature is 220.4 °C, which are greatly lower than those of pure MgH2 and also distinctly lower than those of MgH2 + 5 wt% TiO2 nanoparticles (NP). For isothermal dehydrogenation analysis, the MgH2 + 5 wt% TiO2 NS can release 6.0 wt% hydrogen within 3.2 min at 260 °C and desorb 5.8 wt % hydrogen within 6 min at 240 °C. It is worth noting that the MgH2 + 5 wt% TiO2 NS can even release 1.2 wt% hydrogen at a temperature as low as 180 °C within 300 min. The hydrogenation kinetics of MgH2 + 5 wt% TiO2 NS is also greatly improved, which could absorb hydrogen within only a few seconds at the mild temperature. It can uptake 3.3 wt% hydrogen at 50 °C and 5.4 wt% at 100 °C within 10 s. It is demonstrated that the tremendous enhancement in reaction kinetics of MgH2 can be ascribed to the nanometer size and highly active {001} facets of anatase TiO2. The higher average surface energy can significantly reduce the hydrogen desorption activation energy of MgH2 to 67.6 kJ/mol, thus easily improves the hydrogen desorption properties.
关键词： Magnesium hydride,Hydrogen storage,Catalytic effects,crystal facets,TiO2
更新于2025-11-14 17:03:37
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Insights into the thermo-photo catalytic production of hydrogen from water on a low-cost NiOx-loaded TiO2 catalyst
摘要： Thermo-photo catalytic water splitting, where the introduction of thermal energy increases the oxidation driving force for narrow-band-gap photocatalysts (with a low valence band potential), exhibited significantly advanced performance for hydrogen production compared with general water splitting at room temperature. Herein, a low-cost NiOx-loaded TiO2 catalyst was reported for thermo-photo catalytic water splitting with methanol as the sacrificial agent. The catalyst with an optimal Ni ratio of 5 wt.% achieved a hydrogen evolution rate of 53.7 mmol/h/g under simulated AM 1.5G sunlight at 260℃, which was 2.5 times more than that without illumination, with apparent quantum efficiencies of 66.24%, 33.55%, 32.52% and 15.35% at 380, 420, 450 and 500 nm, respectively. More impressively, under the irradiation of visible light (λ>420 nm) at this temperature, and photohydrogen yield could still reach 26.9 mmol/h/g, which was 5 orders of magnitude greater than that (0.0011 mmol/h/g) conducted at room temperature. Isotope tracer experiments demonstrated that the introduction of photo energy promoted the hydrogen production mainly by enhancing hydrogen evolution from water splitting rather than methanol decomposition or reformation. Furthermore, the step-wise reaction mechanism was revealed with insights into the synergistic roles of thermo-energy and photo-energy for production of hydrogen from water. Those findings highlight the great promise of thermo-photo catalysis and should inspire more efforts for water splitting.
关键词： visible light,Hydrogen production,nickel-based catalysts,thermo-photo catalysis,titanium dioxide
更新于2025-11-14 17:03:37
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Photostable Ratiometric Two-photon Fluorescent Probe for Visualizing Hydrogen Polysulfide in Mitochondria and Its application
摘要： Hydrogen polysulfide (H2Sn) has currently attracted much research interest because it not only plays important physiological function in many biological and health-related events, but also considered as a newfound potent signal transducer. Small-molecule based ratiometric fluorescent probes have advantages in sensitivity and bio-detections but such approaches that intentionally developed for H2Sn detection expected to be mitochondria-accessible are still lacking. In this work, due to that triphenylphosphine group introduced into the molecular scaffold of naphthalimide derivative, Mito-NRT-HP was successfully applied to visualize intracellular H2Sn in mitochondria with excellent aqueous solubility, super photobleaching resistance, favorable cellular membrane permeability and good biocompatibility. This one- and two-photon fluorescent probe with high selectivity and sensitivity (LOD = 0.01 μM) evinced 70-fold enhancement of fluorescence ratio (I546 nm/I478 nm) in the presence of H2Sn over other reactive sulfur species (RSS). The experimental results also give Mito-NRT-HP the potential for mapping the H2Sn distribution in mitochondria and evaluating the H2Sn roles in more biological processes and demonstrated the practical application possibility of Mito-NRT-HP in early diagnosis of LPS-induced acute organ injury.
关键词： mitochondria,fluorescent probe,hydrogen polysulfide,ratiometric,two-photon
更新于2025-11-14 15:29:11
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A comparative study on photocatalytic hydrogen evolution activity of synthesis methods of CDs/ZnIn2S4 photocatalysts
摘要： The introduction of carbon materials in photocatalytic systems can significantly enhance the photocatalytic hydrogen evolution activity. Here, we proposed and fabricated carbon nanodots/ZnIn2S4 (CDs/ZIS) samples via three methods. The morphology, chemical elements and valence, and photoelectric properties of CDs/ZIS samples were systematically characterized by SEM, TEM, XPS, UV and PL. The photocatalytic H2 production experiments indicate that the photocatalytic performance of all CDs/ZIS samples has been significantly improved, which could be attributed to the fact that serving as an excellent electron acceptor, CDs can accelerate the separation efficiency of photogenerated electrons and holes. The samples prepared via one-pot hydrothermal method exhibit the optimal photocatalytic activity and the corresponding H2 production rate of 4.15 mmol g?1 h?1 under visible light irradiation (λ > 420 nm), which is about 2.92 times higher than pure ZIS. Our work presented the influence of synthetic method on photoelectric performance and photocatalytic activity of CDs/ZIS nanocomposites, and provided a reliable idea for improving the photocatalytic performance of photocatalyst toward practical applications.
关键词： Synthesis methods,ZnIn2S4,Photocatalytic hydrogen evolution,Carbon dots
更新于2025-11-14 15:29:11
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Stable Hybrid Perovskite MAPb(I1?Br )3 for Photocatalytic Hydrogen Evolution
摘要： Hybrid organic-inorganic perovskites have been pursuing for solar/visible-driven H2 evolution from hydrohalic acid (HX) splitting, but their inherent structural stability and performance are still challenging. Herein, we report on a stable hybrid perovskite MAPb(I1?xBrx)3 (x = 0 – 0.20) obtained by one-pot crystallization in a mixed halide parent solution and its implementation as a newcomer photocatalyst for H2 evolution in aqueous HX solution. MAPb(I1?xBrx)3 is demonstrated to be a superior visible-light-driven photocatalyst for H2 evolution in aqueous HI/HBr solution with no Pt as a cocatalyst. An optimized MAPb(I1?xBrx)3 (x = 0.10) shows a highest H2 evolution rate of 1471 μmol h?1 g?1 under visible light (λ ≥ 420 nm) illumination, which is ~ 40 times higher than that of pure MAPbI3, and the dual-halide perovskite is rather stable showing no obvious decrease in the photocatalytic activity over 60 runs (252 h). The perovskite inherent structural stability is further evidenced by XRD, UV-vis spectra and EDS elemental mapping of MAPb(I1?xBrx)3 measured after cycled photocatalytic reaction. The solar HI splitting efficiency of MAPb(I1?xBrx)3 (x = 0.10) is determined as 1.42%. The mechanism behind photocatalytic H2 evolution enhancement is elucidated by the experimental and computational methods.
关键词： photocatalyst,MAPb(I1?xBrx)3,hydrogen evolution,perovskite,visible light
更新于2025-11-14 15:28:36
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Construction of dual defect mediated Z-scheme photocatalysts for enhanced photocatalytic hydrogen evolution
摘要： The construction of Z-scheme system is a promising approach for photocatalytic hydrogen evolution (PHE). In this study, we fabricated a direct Z-scheme system consisting of defect-rich g-C3N4 nanosheets (DR-CNNS) crumpled nanosheets with defect-rich TiO2 (DR-TiO2) nanoparticles via a dual defective strategy. The optimized dual-defective rich TiO2/CNNS composite showed a superior PHE rate of ?651.79 μmol/h with a turnover frequency of ?419.3 h?1 as well as high stability and recyclability, which presented the highest value in single defective TiO2 or g-C3N4-based photocatalysts families reported previously. Furthermore, this protocol could also be extended to synthesize other dual defective g-C3N4/oxides (ZnO, SnO2, etc.) heterostructures. The improved photocatalytic performances could be ascribed to the following aspects: (1) rich dual defect, narrowing the band gap and providing more reactive sites for PHE; (2) intimate interface, facilitating interfacial migration and utilization of photogenerated charges; (3) Z-scheme structure, accelerating photogenerated electron-hole pair separation and thus leading to more e?cient PHE. Our work highlights the critical role of defects in construction of Z-scheme system and provides the possibility of utilizing dual defective g-C3N4-based systems for other photocatalytic applications including CO2 reduction and water puri?cation.
关键词： Photocatalytic hydrogen evolution,Dual defect,Oxides/g-C3N4,Heterojunction,Direct Z-scheme
更新于2025-11-14 15:27:09
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Cadmium sulfide nanostructures: Influence of morphology on the photocatalytic degradation of erioglaucine and hydrogen generation
摘要： Size and shape of inorganic materials are known to have great effects on their physical and chemical properties. Here, for the first time we report the visible light driven photocatalytic degradation of erioglaucine – a stable organic dye molecule in the presence of chemically synthesized nanoscale CdS with 1D (nanorods), 2D (nanosheets) and 3D (hierarchical) morphology. Visible light driven photocatalytic degradation efficiency of both 1D and 3D CdS in the removal of erioglaucine are identical. Surprisingly, with 5 min of sonication, the highly crystalline 3D CdS stacked with many thin nanowires containing numerous active surface sites exhibited four-fold enhanced photodegradation efficiency in comparison to 1D and 2D CdS. Scavenger studies revealed that electrons and superoxide radicals are primary reactive species involved in the photodegradation of erioglaucine, while cyclic photodegradation studies revealed the good stability of 3D CdS against photocorrosion. Further, the photocatalytic hydrogen evolution studies also revealed the excellent activity of 3D CdS in comparison to 1D and 2D CdS. Thus, we find that the morphology indeed influences the photocatalytic activity. These results reveal that 3D CdS nanostructures investigated in the present work are efficient photocatalysts that could be fine-tuned for both environmental remediation and hydrogen generation applications.
关键词： erioglaucine,nanostructures,photocatalysis,hydrogen evolution,Cadmium sulfide
更新于2025-11-14 14:48:53
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Visible light active CZTS sensitized CdS/TiO2 tandem photoanode for highly efficient photoelectrochemical hydrogen generation
摘要： A tandem photoanode consisting of Cu2ZnSnS4 (CZTS) nanoparticles layer over CdS/TiO2 heterostructure thin film on FTO substrate has been fabricated for photoelectrochemical hydrogen generation. CdS thin film has been deposited by chemical bath deposition over the spin-coated TiO2 thin film, which is followed by the deposition of CZTS nanoparticles layer by spray coating technique resulting in a CZTS/CdS/TiO2/FTO photoanode. The coating of CZTS nanoparticles layer over CdS/TiO2 films resulted in the tandem structure of different band level positions, which enhances the optical absorption in the visible region and also leads to higher separation of the photogenerated charge carriers. A substantial enhancement (39 times) in the PEC activity has been demonstrated for the CZTS/CdS/TiO2/FTO photoanode as compared to TiO2/FTO photoanode, which is due to cascade band gap from 3.2 eV to 1.7 eV and formation of heterojunction at interfaces. The enhancement in the charge transport properties of CZTS/CdS/TiO2/FTO photoanode has been confirmed from the electrochemical impedance spectroscopy (EIS) measurement. The EIS results confirm that the CZTS/CdS/TiO2/FTO photoanode exhibited lowest charge transfer resistance (Rct = 302 Ω/cm2) as compared to CdS/TiO2 (Rct = 615 Ω/cm2) and TiO2 (Rct = 1700 Ω/cm2) photoanode. A mechanism depicting the enhanced the performance of photoelectrochemical (PEC) CZTS/CdS/TiO2/FTO photoanode has been proposed.
关键词： EIS,Hydrothermal,PEC,Hydrogen generation,CZTS nanoparticles
更新于2025-10-22 19:40:53
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Surface-to-volume ratio drives photoelelectron injection from nanoscale gold into electrolyte
摘要： Hot charge carriers from plasmonic nanomaterials currently receive increased attention due to their promising potential in important applications such as solar water splitting. While a number of important contributions were made on plasmonic charge carrier generation and their transfer into the metal’s surrounding in the last decades, the local origin of those carriers is still unclear. With our study employing a nanoscaled bicontinous network of nanoporous gold, we take a comprehensive look at both subtopics in one approach and give unprecedented insights into the physical mechanisms controlling the broadband optical absorption and the generation and injection of hot electrons into an adjacent electrolyte where they enhance electrocatalytic hydrogen evolution. This absorption behavior is very different from the well-known localized surface plasmon resonance effects observed in metallic nanoparticles. For small ligament sizes the plasmon decay in our network is strongly enhanced via surface collisions of electrons. These surface collisions are responsible for the energy transfer to the carriers, thus, the creation of hot electrons from a broad spectrum of photon energies. As we reduce the gold ligament sizes below 30 nm, we demonstrate an occurring transition from absorption that is purely exciting 5d-electrons from deep below the Fermi level to an absorption which significantly excites “free” 6sp-electrons to be emitted. We differentiate these processes via assessing the internal quantum efficiency of the gold network photoelectrode as a function of the feature size providing a size-dependent understanding of the hot electron generation and injection processes in nanoscale plasmonic systems. We demonstrate that the surface effect - compared to the volume effect – becomes dominant and leads to significantly improved efficiencies. The most important fact to recognize is that in the surface photoeffect presented here, absorption and electron transfer are both part of the same quantum mechanical event.
关键词： Hot electron,Photoemission,Water splitting,Hydrogen evolution,Carrier injection,Surface damping,Nanoporous Au
更新于2025-10-22 19:40:53