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A Three-Dimensional ZnO/CdS/NiFe Layered Double Hydroxide Photoanode Coupled with a Cu <sub/>2</sub> O Photocathode in a Tandem Cell for Overall Solar Water Splitting
摘要： An integrated tandem photoelectrochemical (PEC) cell, composed of a three-dimensional (3D) ZnO/CdS/NiFe layered double hydroxide (LDH) core/shell/hierarchical nanowire arrays (NWAs) photoanode and a p-Cu2O photocathode, was designed for unassisted overall solar water splitting in this study. The optical and photoelectrochemical characteristics of ZnO-based photoanodes and Cu2O photocathode were investigated. The results show that ZnO/CdS/NiFe LDH nanostructures offer significantly enhanced performances with a photocurrent density reaching 5.8 mA cm?2 at 0.9 V and an onset potential as early as 0.1 V (versus RHE). The enhancement can be attributed to the existence of CdS nanoparticles (NPs) which boosts the light absorption in visible region and enhances charge separation. Moreover, the introduction of NiFe LDH nanoplates, with unique hierarchical mesoporous architecture, promotes electrochemical reactions by providing more active sites as co-catalyst. On the above basis, the ZnO/CdS/NiFe LDH–Cu2O two-electrode tandem cell system was established. At zero bias, the device shows a photocurrent density of 0.4 mA cm?2 along with the corresponding solar-to-hydrogen (STH) conversion efficiency reaching 0.50%. Our results indicate that the tandem PEC cells consisting of metal–oxide–semiconductor photoelectrodes based on Earth-abundant and low-cost materials hold promising application potential for overall solar water splitting.
关键词： ZnO,PEC tandem cell,CdS,solar hydrogen,self-driven water splitting,NiFe LDH
更新于2025-09-12 10:27:22
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Optimization Algorithms of Neural Networks for Traditional Time-Domain Equalizer in Optical Communications
摘要： Herein we report an e?ective Ru(NH3)6 3+/Ru(NH3)6 2+-mediated photoelectrochemical-chemical-chemical (PECCC) redox cycling ampli?cation (RCA) strategy toward enhanced triple signal ampli?cation for advanced split-type PEC immunoassay application. Speci?cally, alkaline phosphatase (ALP) label was con?ned via a sandwich immunorecognition to convert 4-aminophenyl phosphate to the signal reporter 4-aminophenol (AP), which was then directed to interact with Ru(NH3)6 2+ as a redox mediator and tris (2-carboxyethyl) phosphine (TCEP) as reducing agent in the detection bu?er. Upon illumination, the system was then operated upon the oxidation of Ru(NH3)6 2+ by the photogenerated holes on the Bi2S3/BiVO4 photoelectrode, starting the chain reaction in which the Ru(NH3)6 2+ was regenerated by Ru(NH3)6 3+-enabled oxidization of AP to p-quinoneimine, which was simultaneously recovered by TCEP. Exempli?ed by interleukin-6 (IL-6) as the analyte, the Ru(NH3)6 3+/Ru(NH3)6 2+-mediated, AP-involved PECCC RCA coupled with ALP enzymatic ampli?cation could achieve triple signal ampli?cation toward the ultrasensitive PEC IL-6 immunoassay. This protocol can be extended as a general basis for other numerous targets of interest. Besides, we believe this work could o?er a new perspective for the further exploration of advanced RCA-based PEC bioanalysis.
关键词： photoelectrochemical-chemical-chemical (PECCC) redox cycling ampli?cation (RCA),triple signal ampli?cation,Bi2S3/BiVO4 photoelectrode,Ru(NH3)6 3+/Ru(NH3)6 2+-mediated,PEC immunoassay
更新于2025-09-11 14:15:04
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An efficient tandem photoelectrochemical cell composed of FeOOH/TiO2/BiVO4 and Cu2O for self-driven solar water splitting
摘要： An integrated solar water splitting tandem cell without external bias was designed using a FeOOH modified TiO2/BiVO4 photoanode as a photoanode and p-Cu2O as a photocathode in this study. An apparent photocurrent (0.37 mA/cm2 at operating voltage of +0.36 VRHE) for the tandem cell without applied bias was measured, which is corresponding to a photoconversion efficiency of 0.46%. Besides, the photocurrent of FeOOH modified TiO2/BiVO4 and Cu2O photocathode (~0.07 mA/cm2 at +0.42 VRHE). Then we established a FeOOH modified TiO2/BiVO4-Cu2O two-electrode system and measured the current density-voltage curves under AM 1.5G illumination. The unassisted photocurrent density is 0.12 mA/cm2 and the corresponding amounts of hydrogen and oxygen evolved by the tandem PEC cell without bias are 2.36 mmol/cm2 and 1.09 mmol/cm2 after testing for 2.5 h. The photoelectrochemical (PEC) properties of the FeOOH modified TiO2/BiVO4 photoanode were further studied to demonstrate the electrons transport process of solar water splitting. This aspect provides a fundamental challenge to establish an unbiased and stabilized photoelectrochemical (PEC) solar water splitting tandem cell with higher solar-to-hydrogen efficiency.
关键词： Self-driven water splitting,PEC tandem cell,Solar hydrogen,Cu2O-BiVO4
更新于2025-09-10 09:29:36
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Compared with a-Fe2O3 and ZnxFe3-XO4 Thin Films Grown by Chemical Spray Pyrolysis
摘要： This work describes hematite (a-Fe2O3) and ZnxFe3-XO4 thin films prepared by Chemical Spray Pyrolysis (CSP) method. CSP method allows an optimal control of stoichiometry and impurity incorporation, hematite films modified with Zn2+ was also prepared. Moreover, the most attracting characteristics of the hematite are its stability in neutral and basic solutions, abundance and band gap energy (2.0–2.2 eV) which permits it to absorb approximately 40% of the incident solar spectrum on earth. Nevertheless, the performance of hematite electrodes for water oxidation is restricted by their poor charge transport properties. Hematite has low conductivity and low charge-carrier mobility. In addition, the photoexcited electron–hole pairs have short life time (~10-12 s), which makes the hole diffusion length to be also short (2–4 nm). The charge transport properties of hematite can be improved by dopping. We demonstrated to increase the conductivity of hematite by dopping it with metal cations with 2+ charges which improved the photocatalytic properties. Doping with metal cations with 2+ charges has also brought good photoelectrochemical results. So we iron oxide and Zn-doped iron oxide compounds have been investigated. The structural, optical and magnetic properties of a-Fe2O3 and ZnxFe3-xO4 compounds have been extensively investigated. XRD, XPS, Raman, FE-SEM and AFM techniques have been used for structural analysis; Absorption technique has been used for optical properties; Hall and Vibrating Sample Magnetometer (VSM) techniques have been used for magnetic properties.
关键词： Hematite,Thin film,Photoelectrochemical (PEC),Zn-doped iron oxide
更新于2025-09-09 09:28:46
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Graphitic Carbon Nitride Impregnated Niobium Oxide (g-C <sub/>3</sub> N <sub/>4</sub> /Nb <sub/>2</sub> O <sub/>5</sub> ) Type (II) Heterojunctions and Its Synergetic Solar-Driven Hydrogen Generation
摘要： Graphitic carbon nitride (g-C3N4) based catalysts are evolving in energy harvesting applications due to their robustness, nontoxicity, and most important photocatalytic efficiencies. In this work, we successfully engineered g-C3N4/Nb2O5 type (II) heterojunction via pulse sonochemical technique based on opposite charge-induced hetero-aggregation on the surface. The agglomerated spherical Nb2O5 nanoparticles (NPs) having diameter 30-40 nm observed on the lamellar surface of g-C3N4 in FESEM images. The XRD and XPS analysis confirm the orthorhombic phase and formation of the g-C3N4/Nb2O5 heterostructure. The FTIR spectra of g-C3N4/Nb2O5 show characteristic poly s-triazine bands from 1250 to 1650 cm-1. Moreover, g-C3N4/Nb2O5 exhibited the lower bandgap value of 2.82 eV as compared to Nb2O5 (3.25eV) with significant redshift and enhance visible light absorption. The Mott-Schottky (MS) analysis confirms the formation of heterojunction between g-C3N4 and Nb2O5, with significant band shifting towards lower hydrogen evolution reaction (HER) potential. The g-C3N4/Nb2O5 heterojunctions showed many folds enhanced photocurrent response from photoelectrochemical (PEC) water splitting, and the value reached to – 0.17 mA/cm2 with good stability and insignificant dark photocurrent at 1.0 V vs RHE. The electrochemical impedance spectroscopic (EIS) measurements further elucidate the suppression of photogenerated electrons/holes as the radius of the semicircle significantly decreased in case of heterojunction formation. The enhanced photocatalytic hydrogen generation by the heterostructures could be attributed to the effective formation of heterojunctions between the g-C3N4 and Nb2O5 semiconductors, causing the migration of the photogenerated electrons and holes, hence increasing their lifetimes.
关键词： Pulse Sonication,PEC Water Splitting,g-C3N4,Photocurrent density,Nb2O5 NPs
更新于2025-09-09 09:28:46
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Specific electron-transfer and surface plasmon resonance integrated boosting visible-light photoelectrochemical sensor for 4-chlorophenol
摘要： Emerging analytical technologies are being developed to provide advanced methods for monitoring 4-chlorophenol (4-CP) in the environment. Herein, a label-free, sensitive, and rapid photoelectrochemical (PEC) 4-CP detection system was constructed based on ternary composites of Ag nanoparticles, graphitic carbon nitride (GCN) and carbon spheres (CS) (Ag/GCN/CS). The proposed ternary composites were synthesized by a simple hydrothermal method. In this process, ascorbic acid (AA) played a crucial role in reducing Ag+ to metallic Ag, and provided a carbon source for CS. Due to synergistic promotion by the surface plasmon resonance (SPR) effect of Ag nanoparticles and electron-transfer behavior of CS, the ternary composites exhibited a broad visible light response and fast charge transfer, leading to a tremendously enhanced PEC response. Based on the promotion of the PEC response, a PEC sensor for 4-CP was designed by detecting the photocurrent signals of the PEC electrode after adding 4-CP to solution. Under optimal conditions, the PEC sensor exhibited a wide linear range for 4-CP from 16 to 1104 ng mL–1, with a limit of detection (LOD) of 5.33 ng mL–1. In particular, the present work may provide assist in better understanding the synergistic effect between the SPR effect of Ag nanoparticles and electron-transfer properties of CS. The results can also be applied to other PEC and photocatalytic systems in conjunction with high-performance photoactive materials.
关键词： PEC sensor,Carbon materials,Electron-transfer,SPR,Ternary composite
更新于2025-09-04 15:30:14
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Studies on Different Doped Zn Concentrations of CdSe Thin Films
摘要： Different Zn concentration was doped with CdSe thin films by Electron Beam Evaporation method. Crystallite variation was studied for doping effect and it was found to be about 40 to 50 nm respectively. Optical band gap values are found to be modified by doping as well as annealing. Annealed films showed considerable influence in their opto-elctronic and structural properties, which provided improvement in conversion efficiency of about 2.75% and 2.87% respectively.
关键词： PEC solar cells,Electron beam evaporation,Doping effect,XRD of CdSe
更新于2025-09-04 15:30:14
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Energy Band Gap Modulation in Nd-doped BiFeO <sub/>3</sub> /SrRuO <sub/>3</sub> Heteroepitaxial for Visible Light Photoelectrochemical Activity
摘要： The ability of band offsets at multiferroic/metal and multiferroic/electrolyte interfaces in controlling charge transfer, and thus alters the photoactivity performance has sparked significant attention in solar energy conversion applications. Here, we demonstrate that the band offsets of the two interfaces play the key role in determining charge transport direction in a downward self-polarized BFO film. Electrons tend to move to BFO/electrolyte interface for water reduction. Our experimental and first-principles calculations reveal that the presence of neodymium (Nd) dopants in BFO enhances the photoelectrochemical performance by reduction of the local electron-hole pair recombination sites and modulation of the band gap to improve the visible light absorption. This opens a promising route to the heterostructure design by modulating the band gap to promote efficient charge transfer.
关键词： density functional theory (DFT),heterojunction band offsets,charge transfer,Nd-doped BiFeO3,photoelectrochemical (PEC)
更新于2025-09-04 15:30:14
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Mixed-Phase (2H and 1T) MoS2 Catalyst for a Highly Efficient and Stable Si Photocathode
摘要： We describe the direct formation of mixed-phase (1T and 2H) MoS2 layers on Si as a photocathode via atomic layer deposition (ALD) for application in the photoelectrochemical (PEC) reduction of water to hydrogen. Without typical series-metal interfaces between Si and MoS2, our p-Si/SiOx/MoS2 photocathode showed efficient and stable operation in hydrogen evolution reactions (HERs). The resulting performance could be explained by spatially genuine device architectures in three dimensions (i.e., laterally homo and vertically heterojunction structures). The ALD-grown MoS2 overlayer with the mixed-phase 1T and 2H homojunction passivates light absorber and surface states and functions as a monolithic structure for effective charge transport within MoS2. It is also beneficial in the operation of p-i-n heterojunctions with inhomogeneous barrier heights due to the presence of mixed-phase cocatalysts. The effective barrier heights reached up to 0.8 eV with optimized MoS2 thicknesses, leading to a 670 mV photovoltage enhancement without employing buried Si p-n junctions. The fast-transient behaviors via light illumination show that the mixed-phase layered chalcogenides can serve as efficient cocatalysts by depinning the Fermi levels at the interfaces. A long-term operation of ~70 h was also demonstrated in a 0.5 M H2SO4 solution.
关键词： pinch-off effect,molybdenum disulfide,photoelectrochemical water splitting (PEC),p-i-n heterojunction,atomic layer deposition (ALD)
更新于2025-09-04 15:30:14
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Ag?Au‐Bimetal Incorporated ZnO‐Nanorods Photo‐Anodes for Efficient Photoelectrochemical Splitting of Water
摘要： Plasmonic Ag(cid:0) Au/ZnO nanorods (ZNRs) based photo-anodes were synthesized using a simple electrochemical route and were then evaluated for photoelectrochemical (PEC) activity. The amalgamation of Ag and Au nanoclusters broadens the UV-Vis light absorption in the range of 400 nm to 650 nm. Ag(cid:0) Au/ZNRs photo-anodes had shown photo-current density of ~ 1.4 mA cm(cid:0) 2, at a bias of 0.75 V/SCE, which is ~ 3.1 times of bare ZNRs photo-anode. Bi-metallic Ag(cid:0) Au/ZNRs based photo-anode shows the maximum photo-conversion efficiency of 0.77 % at 0.5 V/SCE, under one sun illumination. Formation of hot electrons in Ag(cid:0) Au/ ZNRs photo-anodes can be partly held responsible for the enhanced PEC activity. Au/Ag core/shell morphology evolves when a thin layer of Ag is loaded on Au nanoparticles. For an in-depth analysis on Ag(cid:0) Au incorporated ZNRs based photo-anodes and its PEC activity, a detailed characterization was carried out using physico-chemical, spectral and microscopy techniques. The analysis shows that Au in direct contact with ZnO interacts mainly with oxygen vacancies present on surface of ZnO and Ag interacts with Au for an effective electron-hole segregation process at interface and electron storage occurs in metal nanoparticles. The results suggest bi-metal incorporated ZNRs based photo-anodes can be a prospective candidate for PEC water splitting application.
关键词： Water splitting,Incident photon to current conversion efficiency (IPCE),Bi-metal photo-anodes,Electrodeposition,PEC activity
更新于2025-09-04 15:30:14