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Multifunctional p‐Type Carbon Quantum Dots: a Novel Hole Injection Layer for High‐Performance Perovskite Light‐Emitting Diodes with Significantly Enhanced Stability
摘要： Excess electrons from intrinsic oxygen vacancies play a key role in the surface chemistry and catalytic properties of metal oxides. This effect in actinide dioxides is particularly critical (AnO2), the most common nuclear fuels, where radiation can induce the formation of vacancies. However, the behavior of excess electrons on AnO2 surfaces has not been fully explored. In this article, we present a first-principle study of the electronic structure of excess electrons from oxygen vacancies on AnO2 (111) surfaces (An = Th, U, Pu). The low-energy solutions for the excess electrons are searched via U-ramping and occupation matrix control. The excess electrons are found to localize at the vacancy site on ThO2 and move to the metal 5f orbitals on the PuO2 surface, with UO2 as the intermediate case. This change significantly affects the catalytic properties of the AnO2 surfaces. In the presence of water, the excess electrons lead to the exothermic splitting of H2O and formation of molecular H2 on ThO2 and UO2 surfaces, while on the PuO2 surface the formation of H2 is thermodynamically unfavorable. This work has vital implications in the surface chemistry and corrosion of AnO2 and hence the handling and long-term storage of spent nuclear fuels.
关键词： oxygen vacancies,catalytic properties,nuclear fuels,excess electrons,actinide dioxides,water splitting
更新于2025-09-11 14:15:04
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Photo-driven water splitting photoelectrochemical cells by tandem organic dye sensitized solar cells with I?/I3? as redox mediator
摘要： Dye-sensitized photoelectrochemical tandem cells have shown the promise for light driven hydrogen production from water owing to the low cost, wide absorption spectra in the visible region and ease to process of their constitutive photoelectrode materials. However, most photo-driven water splitting photoelectrochemical cells driven by organic dye sensitized solar cells exhibit unsatisfactory hydrogen evolution rate, primarily attributed to their poor light capturing ability and low photocurrent performance. Here we present the construction of a tandem system consisting of an organic blue-colored S5 sensitizer-based dye-sensitized photoelectrochemical cell (DSPEC) wired in series with three spectral-complemental dyes BTA-2, APP-3 and APP-1 sensitizers-based dye-sensitized solar cell (DSC), respectively. The two spectral-complemental chromophores were used in DSC and DSPEC to ensure that the full solar spectrum could be absorbed as much as possible. The results showed that the photocurrent of tandem device was closely related to the open-circuit voltage (Voc) of sensitized DSC, in which the tandem configuration consisting of S5 based DSPEC and BTA-2 based DSC gave the best photocurrent. On this basis, tandem device with the only light energy and no external applied electrical bias was further constructed of BTA-2 based 2-junction DSC and S5 based DSPEC and obtained a photocurrent of 500 μA cm?2 for hydrogen generation. Furthermore, I?/I3 ? was used as a redox couple between dye regeneration and O2 production on the surface of Pt-IrO2/WO3. The strategy opens up the application of pure organic dyes in DSC/DSPEC tandem device.
关键词： dye-sensitized photoelectrochemical cells,water splitting,tandem device,dye-sensitized solar cells
更新于2025-09-11 14:15:04
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Phase-junction design of MOF-derived TiO2 photoanodes sensitized with Quantum Dots for efficient hydrogen generation
摘要： Photoelectrochemical (PEC) water splitting is a promising and environmentally friendly pathway for exploiting renewable energy sources, to address the ever-growing demand for clean energy. Due to its excellent photostability and favorable band alignment, titanium dioxide (TiO2) is the one of the most common metal oxide for water splitting. However, the efficiency in TiO2-based PEC systems is limited by the high recombination of photo-generated electron/hole pairs and large intrinsic band gap (3.2 eV) which limit the absorption of the sunlight. Herein, we explore a simple metal organic framework (MOF)-derived synthesis to obtain a controlled mixed-phase (anatase and rutile) of TiO2 nanoparticles, which retain the MOF crystal morphology. Compared with commercial TiO2 films, the MOF-derived TiO2 film sensitized by core-shell CdSe@CdS QDs, showed an enhanced PEC device stability of +42.1% and PEC performance of +47.6%. The enhanced performance is due to the presence of the mixed rutile/anatase phases, that creates a favorable band energy alignment for the separation of the photogenerated charges. The proposed MOF-derived TiO2 is an efficient strategy to improve the efficiency of the TiO2-QDs heterojunction based PEC system for hydrogen generation.
关键词： Metal organic framework,Mixed-phase TiO2,Photoelectrochemical water splitting,Quantum dots,Hydrogen generation
更新于2025-09-11 14:15:04
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A Scalable Laser-assisted Method to Produce Active and Robust Graphene-supported Nanoparticle Electrocatalysts
摘要： The development of renewable energy schemes requires the scalable production of highly robust electrocatalysts using a sustainable synthesis process that does not generate toxic liquid wastes. Here, an industrial laser system is utilized to prepare electrocatalysts in a continuous fashion using a laser-induced-forward-transfer-assisted nanomaterial preparation (LANP) method without generating liquid wastes. This dry processing method at room temperature and under ambient pressure enables the production of well-dispersed Pt, Ru, and Ni nanoparticles (NPs) supported on a few-layer graphene carbon framework. This versatile LANP procedure allows for the efficient deposition of binder-free Pt, Ru, and Ni NPs onto flexible polyimide films and glass surfaces at a rate of 400 mm/s. The size and quantity of the spherical NPs present on the conductive carbon surface can be tuned by adjusting the LANP parameters such as the laser power, the scribing speed, and the source thickness. Upon increasing the laser power, the Pt NPs size decreases, and the amount of Pt in the laser-derived materials increases. A second laser treatment can further modulate the hydrophilicity and solvent accessibility of graphene-supported Pt NPs. Our results demonstrate that the binder-free Pt, Ru, and Ni NPs supported on few-layer graphene generated using the LANP strategy can serve as practical, active, and robust electrocatalysts for water splitting reactions in advanced electrolyzer technology.
关键词： laser-assisted,graphene,electrocatalysts,water splitting,nanoparticles
更新于2025-09-11 14:15:04
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Overall water splitting and hydrogen peroxide synthesis by gold nanoparticle-based plasmonic photocatalysts
摘要： Gold nanoparticle-based plasmonic photocatalysts can be driven by excitation of the localized surface plasmon resonance. Among them, hot-electron transfer-type photocatalysts have recently attracted interest as promising solar-to-chemical converters owing to the wide spectral response from visible-to-infrared light. This Minireview highlights recent studies on two kinds of artificial photosynthesis - water splitting and H2O2 synthesis from water and oxygen - using hot-electron transfer-type plasmonic photocatalysts with particular emphasis placed on the electrocatalysis of Au nanoparticles.
关键词： water splitting,gold nanoparticle,hot-electron transfer,hydrogen peroxide synthesis,plasmonic photocatalysts
更新于2025-09-11 14:15:04
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Long-term stabilized high-density CuBi <sub/>2</sub> O <sub/>4</sub> /NiO heterostructure thin film photocathode grown by pulsed laser deposition
摘要： Harvesting sustainable hydrogen through water-splitting requires a durable photoelectrode to achieve high efficiency and long lifetime. Dense, uniform CuBi2O4/NiO thin film photocathodes grown by pulsed laser deposition achieved photocurrent density over 1.5 mA cm-2 at 0.4 VRHE and long-term chronoamperometric stability for over 8 hours.
关键词： heterostructure,pulsed laser deposition,water-splitting,CuBi2O4,NiO,hydrogen,photocathode
更新于2025-09-11 14:15:04
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Designing WO <sub/>3</sub> /CdIn <sub/>2</sub> S <sub/>4</sub> type-II heterojunction with both efficient light absorption and charge separation for enhanced photoelectrochemical water splitting
摘要： WO3 is a typical photoanode material for photoelectrochemical (PEC) water splitting. However, the PEC activity of WO3 photoanode is limited by its poor visible light absorption as well as severe carrier recombination at the electrode/electrolyte interface. Herein, we integrate small-band-gap CdIn2S4 nanoplates with hydrothermally grown WO3 nanowall arrays to form into a three-dimensional (3D) WO3/CdIn2S4 heterojunction through a chemical bath deposition process. The synthesis parameters of CdIn2S4, including reaction time and temperature, have been tuned to optimize the PEC performance. The WO3/CdIn2S4 composite photoanode prepared at 50 °C for 5 h exhibits the highest photocurrent of 1.06 mA cm?2 at 1.23 V versus reversible hydrogen electrode without the presence of holes scavenger, which is about 5.9 times higher than that of bare WO3 photoanode. The band alignment between WO3 and CdIn2S4 is confirmed by the ultraviolet–visible light absorption spectra and ultraviolet photoelectron spectra. The PEC performance enhancement is attributed to the enhanced light absorption benefiting from the small band gap of CdIn2S4 and efficient charge separation originating from the type-II alignment between WO3 and CdIn2S4.
关键词： photoanode,WO3,CdIn2S4,photoelectrochemical water splitting,heterojunction
更新于2025-09-11 14:15:04
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Synthesis of Plasmonic Photocatalysts for Water Splitting
摘要： Production of H2, O2, and some useful chemicals by solar water splitting is widely expected to be one of the ultimate technologies in solving energy and environmental problems worldwide. Plasmonic enhancement of photocatalytic water splitting is attracting much attention. However, the enhancement factors reported so far are not as high as expected. Hence, further investigation of the plasmonic photocatalysts for water splitting is now needed. In this paper, recent work demonstrating plasmonic photocatalytic water splitting is reviewed. Particular emphasis is given to the fabrication process and the morphological features of the plasmonic photocatalysts.
关键词： metal nanostructure,solar water splitting,surface plasmon resonance,semiconductor,metal nanoparticle
更新于2025-09-11 14:15:04
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Photoelectrochemical Water Splitting using Adapted Silicon Based Multi-Junction Solar Cell Structures: Development of Solar Cells and Catalysts, Upscaling of Combined Photovoltaic-Electrochemical Devices and Performance Stability
摘要： Thin film silicon based multi-junction solar cells were developed for application in combined photovoltaic electrochemical systems for hydrogen production from water splitting. Going from single, tandem, triple up to quadruple junctions, we cover a range of open circuit voltages from 0.5 V to 2.8 V at photovoltaic cell (PV) efficiencies above 13%. The solar cells were combined with electrochemical (EC) cells in integrated devices from 0.5 cm2 to 64 cm2. Various combinations of catalyst pairs for the oxygen and hydrogen evolution reaction side (OER and HER) were investigated with respect to electrochemical activity, stability, cost and – important for the integrated device – optical quality of the metal catalyst on the HER side as back reflector of the attached solar cell. The combined PV-EC systems were further investigated under varied operation temperatures and illumination conditions for estimation of outdoor performance and annual fuel production yield. For 0.5 cm2 size combined systems a maximum solar-to-hydrogen efficiency ηSTH = 9.5% was achieved under standard test conditions. For device upscaling to 64 cm2 various concepts of contact interconnects for reduced current and fill factor loss when using large size solar cells were investigated. To replace high performance noble metal based catalyst pairs (Pt/RuO2 or Pt/IrOx), more abundant and cheaper NiMo (HER) and NiFeOx (OER) compounds were prepared via electrodeposition. With the NiMo/NiFeOx catalyst pair we obtained ηSTH = 5.1% for a 64 cm2 size solar cell which was even better than the performance of the Pt/IrO2 system (ηSTH = 4.8%). In simulated day-night cycle operation the NiMo/NiFeOx catalyst pair showed excellent stability over several days. The experimental studies were successfully accompanied by simulation of the entire PV-EC device using a series connection model which allowed studies and pre-estimations of device performance by varying individual components such as catalysts, electrolytes, or solar cells. Based on these results we discuss the prospects and challenges of integrated PV-EC devices on large area for hydrogen and solar fuel production in general.
关键词： water splitting,photovoltaic-electrochemical system,upscaling,silicon solar cells
更新于2025-09-11 14:15:04
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Photocatalytic properties of TiO2 and Fe-doped TiO2 prepared by metal organic framework-mediated synthesis
摘要： The Ti-containing metal organic framework (MOF) MIL-125 has been used as sacrificial precursor to obtain TiO2 materials through the MOF-mediated synthesis route. In this study, Fe3+ was deposited on the surface of MIL-125 after its hydrothermal synthesis. Targeted Fe-doped titania photocatalysts were prepared through the direct calcination in air of Fe/MIL-125 crystals and/or by using a two-step method, including carbonization in inert atmosphere followed by calcination in air. The relationship between the synthesis conditions and the properties of the Fe-doped titania nanopowders, such as Fe content, porosity, phase composition and particle size was investigated. From elemental mapping, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, UV–Vis absorption spectroscopy and photoluminescence emission spectra, the presence of highly dispersed Fe3+ ions incorporated into the TiO2 crystal lattice was confirmed, which led to a significant red shift of photoresponse towards visible light and reduced the recombination rate of electron-hole pairs at low iron content. By varying the pre-carbonization temperature, both crystal size and phase composition in the final materials were modulated. The performance of Fe-doped titania materials in photocatalytic water-splitting was tested for hydrogen evolution. Optimal photocatalytic performance was found at 0.15 and 0.5 wt. % iron concentration and exceeded those of non-doped titania and commercial anatase both under visible and UV light irradiation, respectively, and among the highest reported in literature for these systems.
关键词： water splitting,Metal Organic Frameworks,H2 production,MOF-mediated synthesis,Fe-doped titania
更新于2025-09-11 14:15:04