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Performance of Graphenea??CdS Hybrid Nanocomposite Thin Film for Applications in Cu(In,Ga)Se2 Solar Cell and H2 Production
摘要： A graphene–cadmium sulfide (Gr–CdS) nanocomposite was prepared by a chemical solution method, and its material properties were characterized by several analysis techniques. The synthesized pure CdS nanoparticles (NPs) and Gr–CdS nanocomposites were confirmed to have a stoichiometric atomic ratio (Cd/S = 1:1). The Cd 3d and S 2p peaks of the Gr–CdS nanocomposite appeared at lower binding energies compared to those of the pure CdS NPs according to X‐ray photoelectron spectroscopy analyses. The formation of the Gr–CdS nanocomposite was also evidenced by the structural analysis using Raman spectroscopy and X‐ray diffraction. Transmission electron microscopy confirmed that CdS NPs were uniformly distributed on the graphene sheets. The absorption spectra of both the Gr–CdS nanocomposite and pure CdS NPs thin films showed an absorption edge at 550 nm related to the energy band gap of CdS (~2.42 eV). The Cu(In,Ga)Se2 thin film photovoltaic device with Gr–CdS nanocomposite buffer layer showed a higher electrical conversion efficiency than that with pure CdS NPs thin film buffer layer. In addition, the water splitting efficiency of the Gr–CdS nanocomposite was almost three times higher than that of pure CdS NPs.
关键词： cadmium sulfide,Gr–CdS,Cu(In, Ga)Se2,buffer layer,water splitting
更新于2025-09-19 17:13:59
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Elucidating the Pulsed Laser Deposition Process of BiVO <sub/>4</sub> Photoelectrodes for Solar Water Splitting
摘要： BiVO4 thin films for the use as photoelectrodes for solar water splitting are prepared by pulsed laser deposition (PLD), a powerful technique to synthesize compact multinary metal oxides films with a high electronic quality. Here, the PLD process of BiVO4 films by ablating a BiVO4 target is systematically elucidated with a special focus on deviations from an ideal stoichiometric target-to-substrate material transfer. By correlating the V:Bi ratio of the films with their charge carrier transport properties and PEC performance, AM1.5 sulfite oxidation photocurrents of ~2.4 mA cm-2 at E = 1.23 V vs. RHE with stoichiometric films are achieved without any deliberate doping or surface modification. In addition, we prepare BiVO4 photoelectrodes for the first time by the alternating ablation of Bi2O3 and V2O5 targets. This approach is found to be an attractive alternative route to control the cation stoichiometry and produces BiVO4 films that generate AM1.5 sulfite oxidation photocurrents of up to 2.6?mA cm-2 at E = 1.23 V vs. RHE. Our results provide important insights into the PLD process of ternary oxide semiconductors and help to accelerate the synthesis and investigation of new multinary metal oxide photoelectrodes.
关键词： pulsed laser deposition,solar water splitting,stoichiometry,BiVO4,photoelectrodes
更新于2025-09-19 17:13:59
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Enhanced Light Absorption and Charge Carrier Management in Core‐Shell Fe2O3@Nickel Nanocone Photoanodes for Photoelectrochemical Water Splitting
摘要： Solar driven photoelectrochemical (PEC) water splitting is a clean and sustainable approach to generate green fuel, Hydrogen. Hematite (Fe2O3) is considered as potential photoanode because of its abundance, chemical stability and suitable band gap, though its short carrier diffusion length puts a limit on the film thickness and subsequent light absorption capability. In this regard, here we have designed and constructed a unique photoanode by depositing ultrathin films of Fe2O3 on purpose-built three-dimensional (3D) nickel nanocone arrays. In this design, 3D nanostructures not only provide ameliorated surface area for PEC reactions but also enhance light absorption capability in ultrathin Fe2O3 films, while ultrathin films promote charge carrier separation and effective transfer to the electrolyte. The 3D electrodes exhibit a substantial improvement in light absorption capability within the entire visible region of solar spectrum, as well as enhanced photocurrent density as compared to the planar Fe2O3 photoelectrode. Detailed investigation of reaction kinetics suggests an optimum Fe2O3 film thickness on 3D nanocone arrays obtained after 6 deposition cycles in achieving maximum charge carrier separation and transfer efficiencies (82% and 88%, respectively), mainly ascribable to the increased charge carrier lifetime overcoming recombination losses.
关键词： photoanode,nanocones,water splitting,ultrathin,photoelectrochemical
更新于2025-09-19 17:13:59
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Controlled Synthesis of CuCo <sub/>2</sub> S <sub/>4</sub> @Ni(OH) <sub/>2</sub> Hybrid Nanorod Arrays for Water Splitting at an Ultralow Cell Voltage of 1.47?V
摘要： Developing environmentally friendly and highly active water splitting catalysts would be of great significance for clean energy conversion and utilization processes. Heterogeneous CuCo2S4@Ni(OH)2 nanorod arrays with abundant oxygen vacancy firstly have been designed through a controllable hydrothermal and electrodeposition method. The synergies and open structures of the particular hierarchical structure together with the abundant oxygen vacancies offer more surface reactive centers, which can promote the electron transfer rate and reduce the activation energy of intermediate species. The CuCo2S4@Ni(OH)2–20 min nanorod arrays are considered as an excellent and robust electrocatalyst for the proton reduction under an alkaline condition with an extraordinary low overpotential of 117 mV at 10 mA cm@2. The CuCo2S4@Ni(OH)2–20 min heterostructures electrode is also stable and robust for the water oxidation reaction, needing an overpotential of only 250 mV to obtain 100 mA cm@2. Therefore, an alkaline electrolyzer was designed using CuCo2S4@Ni(OH)2–20 min nanorod arrays as bifunctional electrocatalyst, which can complete overall water splitting at a cell voltage of 1.47 V with 10 mA cm@2, suggesting a promising combination of the same material for efficient overall water splitting device. The cell voltage of 1.47 V, to our knowledge, is among the lowest values of the published support catalysts for electrocatalytic water splitting up to now.
关键词： stability,Ni foam,water splitting,electrocatalytic,CuCo2S4@Ni(OH)2
更新于2025-09-19 17:13:59
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Interactions of plasmonic silver nanoparticles with high energy sites on multi‐faceted rutile TiO? photoanodes
摘要： The plasmonic interactions between silver nanoparticles and various rutile TiO2 facets are studied by correlating Advanced Electron Microscopy and Electrochemical Impedance Spectroscopy (EIS) to help design a route towards an optimised polycrystalline film fabrication. By using an Electron Backscatter Diffraction (EBSD) detector, it was determined that using HF as directing agent during the hydrothermal growth of TiO2 promotes the formation of high-angle grain boundaries. Silver photodeposition occurs preferentially at these boundaries, consistent with the presence of high energy sites on the (100)-oriented rutile TiO2 nanorods. Further EIS study showed an increase in the photoelectrochemical activity in the visible range of the solar spectrum for the samples consisting of silver nanoparticles deposited on these grain boundaries.
关键词： Water Splitting,Photoelectrochemistry,Plasmonic enhancement,Electron Microscopy,Grain Boundaries
更新于2025-09-19 17:13:59
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Type-II/type-II band alignment to boost spatial charge separation: A case study of g-C3N4 quantum dot/a-TiO2/r-TiO2 for highly efficient photocatalytic hydrogen and oxygen evolution
摘要： Efficient spatial charge separation and transfer that are critical factors for solar energy conversion primarily depend on the energetic alignment of the band edges at interfaces in heterojunctions. Herein, we first report that constructing 0D/0D type-II(T-II)/T-II heterojunction is an effective strategy to ingeniously achieve long-range charge separation by taking a ternary heterojunction of TiO2 and graphitic carbon nitride (g-C3N4) as a proof-of-concept. Incorporating g-C3N4 quantum dots (QCN), as the third component, into the commercial P25 composed of anatase (a-TiO2) and rutile (r-TiO2) can be realized via simply mixing the commercially Degussa P25 and QCN solution followed by heat treatment. The strong coupling and matching band structures among a-TiO2, r-TiO2 and QCN result in the construction of novel T-II/T-II heterojunctions, which would promote the spatial separation and transfer of photogenerated electrons and holes. Moreover, QCN plays a key role in reinforcing light absorption. Specially, the unique 0D/0D architecture possesses the advantages of abundant active sites for photocatalytic reaction. As a result, the optimized QCN/a-TiO2/r-TiO2 heterojunctions exhibit enhanced photocatalytic H2 and O2 evolution, especially the hydrogen evolution rate (49.3 μmol h?1) is 11.7 times that of bare P25 under visible light irradiation, and sufficiently catalytic stability as evidenced by the recycling experiments. The remarkable enhanced photocatalytic activity can be attributed to the synergistic effects of the energy level alignment at interfaces, the dimensionality and component of the heterojunctions. This work provides a stepping stone towards the design of novel heterojunctions for photocatalytic water splitting.
关键词： type-II/type-II band alignment,0D/0D heterojunction,photocatalytic water splitting,g-C3N4 quantum dots,TiO2
更新于2025-09-19 17:13:59
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Stable and durable laser-induced graphene patterns embedded in polymer substrates
摘要： The stability and durability of laser-induced graphene (LIG) patterns embedded in polymer substrates are significant for their practical application. However, most of currently reported LIG precursors are facing the dilemma of weak structural controllability, poor resistance to acid/base, or bad processability. In this work, we efficiently converted the synthesized poly(Ph-ddm) into LIG using a straightforward CO2 laser, aiming to find a potential LIG precursor with excellent durability under harsh conditions. The graphene structure of obtained LIG was confirmed by Raman spectra, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Results indicated that the poly(Ph-ddm)-based LIG showed a low sheet resistance of 35 ?/sq as well as a high specific surface area of 883 m2/g. And due to the superior properties of poly(Ph-ddm), the LIG patterns exhibited excellent resistance to strong acid/base solutions and high adhesion on the substrate, which ensured their stable application under severe conditions. Besides, potential application of as-prepared LIG was demonstrated in well-performed supercapacitors and electrode for water splitting in an alkaline medium. Based on the results in this work, polybenzoxazine could be a promising precursor for stable and durable LIG preparation.
关键词： electrode for water splitting,laser-induced graphene,durability,supercapacitor,Polybenzoxazine
更新于2025-09-19 17:13:59
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Annealed Polycrystalline TiO <sub/>2</sub> Interlayer of the n-Si/TiO <sub/>2</sub> /Ni Photoanode for Efficient Photoelectrochemical Water Splitting
摘要： High photovoltage generation from a photoelectrode is important for efficient solar-driven water splitting. Here, we report a thermal treatment process that greatly enhances photovoltage generation from an n-Si/TiO2/Ni photoanode. By selectively annealing the TiO2 interlayer, the photoanode generates a high photovoltage of 570 mV, which is very competitive as compared with photovoltages produced using other similar metal?insulator?semiconductor structures with earth-abundant metal catalysts. Different annealing conditions and junction layer thicknesses were systematically investigated. It is found that the optimal annealing temperature occurs between 500 and 600 °C. Within this temperature range, the deposited amorphous Ti is converted into polycrystalline anatase phase TiO2. The optimal annealing time scales linearly with TiO2 thickness and inversely with annealing temperature. The large photovoltage generation is attributed to the reduced defect states and improved junction barrier height by the annealed TiO2 interlayer. This study demonstrates that thermal annealing offers an attractive approach to modify the TiO2 interlayer material’s properties for photovoltage optimization.
关键词： photovoltage,photoanode,water splitting,thermal annealing,photoelectrochemistry,junction interlayer
更新于2025-09-19 17:13:59
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Electrochemical Fabrication of rGO-embedded Ag-TiO2 Nanoring/Nanotube Arrays for Plasmonic Solar Water Splitting
摘要： Effective utilization of hot electrons generated from the decay of surface plasmon resonance in metal nanoparticles is conductive to improve solar water splitting efficiency. Herein, Ag nanoparticles and reduced graphene oxide (rGO) co-decorated hierarchical TiO2 nanoring/nanotube arrays (TiO2 R/T) were facilely fabricated by using two-step electrochemical anodization, electrodeposition, and photoreduction methods. Comparative studies were conducted to elucidate the effects of rGO and Ag on the morphology, photoresponse, charge transfer, and photoelectric properties of TiO2. Firstly, scanning electron microscope images confirm that the Ag nanoparticles adhered on TiO2 R/T and TiO2 R/T-rGO have similar diameter of 20 nm except for TiO2 R-rGO/T. Then, the UV–Vis DRS and scatter spectra reveal that the optical property of the Ag-TiO2 R/T-rGO ternary composite is enhanced, ascribing to the visible light absorption of plasmonic Ag nanoparticles and the weakening effect of rGO on light scattering. Meanwhile, intensity-modulated photocurrent spectroscopy and photoluminescence spectra demonstrate that rGO can promote the hot electrons transfer from Ag nanoparticles to Ti substrate, reducing the photogenerated electron–hole recombination. Finally, Ag-TiO2 R/T-rGO photoanode exhibits high photocurrent density (0.98 mA cm?2) and photovoltage (0.90 V), and the stable H2 evolution rate of 413 μL h?1 cm?2 within 1.5 h under AM 1.5 which exceeds by 1.30 times than that of pristine TiO2 R/T. In line with the above results, this work provides a reliable route synergizing rGO with plasmonic metal nanoparticles for photocatalysis, in which, rGO presents a broad absorption spectrum and effective photogenerated electrons transfer.
关键词： TiO2 nanoring/nanotube hierarchical structure,Spectral responses,Plasmonic Ag nanoparticles,Reduced graphene oxide,Water splitting
更新于2025-09-16 10:30:52
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Ultrafast fabrication of Cu oxide micro/nano-structures via laser ablation to promote oxygen evolution reaction
摘要： Despite the tremendous efforts on the preparation of efficient oxygen evolution reaction (OER) electrocatalysts, it is still a challenge to fabricate stable OER electrocatalysts with good performance on a large scale in a simple, fast, green, and environment-friendly way. Herein, we report a simple way via femtosecond laser ablation to fabricate Cu oxide micro/nano-structures on Cu foams by fine-tuning of the laser parameters. The present method is ultrafast, non-contact, high efficiency, easy control, sustainable, and environment-friendly. The fabricated catalysts exhibit remarkable OER activity and excellent durability in 1 M KOH.
关键词： Water splitting,Laser ablation,Metal oxides,Oxygen evolution reaction
更新于2025-09-16 10:30:52