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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
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A revisit to atomic layer deposition of zinc oxide using diethylzinc and water as precursors
摘要： Nanophase zinc oxide (ZnO) has been widely studied as an important multi-functional material in many applications. Atomic layer deposition (ALD) is a unique thin-film synthesis technique, featuring its extreme uniformity, unrivaled conformal coverage, low deposition temperature, and precise controllability. Using diethylzinc (DEZ) and water as precursors, ALD has been reported previously for growing nanophase ZnO thin films. However, the growth characteristics and the resultant ZnO crystallinity have not been well characterized and understood. To this end, we revisited the ALD process of ZnO using DEZ and water. Through employing a suite of advanced characterization techniques, we systematically addressed the growth characteristics, morphological changes, and the crystallinity evolution of ZnO along with growth temperature in the range of 30–250 °C. The growth characteristics of the ALD ZnO films were investigated using in situ quartz crystal microbalance (QCM), scanning electron microscopy, atomic force microscopy, and synchrotron-based X-ray reflectivity. The crystallinity of the ALD ZnO films was determined using synchrotron-based X-ray diffraction and high-resolution transmission electron microscopy. In addition, through further analyzing QCM data, we proposed the adsorption-limited surface reaction for ALD ZnO growth with the temperature-dependent number of –OH surface group reacting with one DEZ molecule. Thus, this study contributes to offer new and deep insights on the fundamental ALD process of ZnO.
关键词： Atomic layer deposition,Water,Diethylzinc,Crystallinity,Zinc oxide,Growth characteristics
更新于2025-09-04 15:30:14
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Phase and Defect Engineering of MoS <sub/>2</sub> Stabilized in Periodic TiO <sub/>2</sub> Nanoporous Film for Enhanced Solar Water Splitting
摘要： Phase and defect engineering of the heterostructured MoS2@TiO2 nanoporous film is investigated to achieve a broad solar spectrum light absorption and high solar water splitting efficiency. The phase transition from the semiconducting 2H-MoS2 to the metallic 1T-MoS2 is achieved by a hydrothermal exfoliation treatment. Experimental studies elucidate that the solar water splitting activity is greatly improved by forming 1T-MoS2 along with increasing S-vacancies because of the significantly enhanced surface plasmon resonance. The mixed-phase MoS2@TiO2 film shows a high H2 yield rate of 308 μmol h?1 cm?2 and long-term durability for 30 h, which is superior to the state-of-the-art catalysts for solar water splitting. This study offers a universal and efficient avenue to rationalize the plasmonic catalysts for solar water splitting and other energy and environmental applications.
关键词： solar water splitting,defect engineering,MoS2,heterostructures,phase transitions
更新于2025-09-04 15:30:14
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Economic analysis of water production from atmospheric air using Scheffler reflector
摘要： In this paper, the economics analysis of water production by using different solid desiccant materials and composite materials through Scheffler reflector is presented. The experiments for water production have been performed at National Institute of Technology, Kurukshetra, Haryana, India [29°58′ (latitude) North and 76°53′ (longitude) East]. The various factors have been carried out to calculate the annual cost/liter in Indian currency. Total six cases are studied, and for each case, uniform procedure is adopted. The silica gel gives the best economical annual cost/liter compared to molecular sieve and activated alumina in case of solid desiccant, and for composite material, it is CaCl2/River Sand compared to LiCl/River Sand and LiBr/River sand.
关键词： Economic analysis,Water production,Scheffler reflector,Desiccant material
更新于2025-09-04 15:30:14
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Wavelength selection of the multispectral lidar system for estimating leaf chlorophyll and water contents through the PROSPECT model
摘要： The estimation of leaf biochemical constituents is of high interest for the physiological and ecological applications of remote sensing. The multispectral lidar (MSL) system emerges as a promising active remote sensing technology with the ability to acquire both three-dimensional and spectral characteristics of targets. The detection wavelengths of the MSL system can be geared toward the specific application purposes. Therefore, it’s important to conduct the wavelength selection work to maximize the potential of the MSL system in vegetation monitoring. Traditional strategies of wavelength selection attempt to establish an empirical relationship between large quantities of observed reflectance and foliar biochemical constituents. By contrast, this study proposed to select wavelengths through the radiative transfer model PROSPECT. A five-wavelength combination was established to estimate leaf chlorophyll and water contents: 680, 716, 1104, 1882 and 1920 nm. The consistency of the wavelengths selected were tested by running different versions of PROSPECT model. Model inversion using simulated and experimental datasets showed that the selected wavelengths have the ability to retrieve leaf chlorophyll and water contents accurately. Overall, this study demonstrated the potential of the MSL system in vegetation monitoring and can serve as a guide in the design of new MSL systems for the application community.
关键词： Multispectral lidar,Wavelength selection,Leaf water content,Leaf chlorophyll content,PROSPECT model
更新于2025-09-04 15:30:14
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Tuning CuOx-TiO2 interaction and photocatalytic hydrogen production of CuOx/TiO2 photocatalysts via TiO2 morphology engineering
摘要： CuOx/TiO2 photocatalysts prepared with anatase TiO2 nanocrystals exposing different types of facets as supports were examined for photocatalytic H2 production in methanol/water solution under simulated solar light. Catalyst structures were characterized by XRD, HRTEM, XPS, UV–vis, EPR, PL, H2-TPR and CO chemisorption. Enhanced photocatalytic H2 productions of CuOx/TiO2 photocatalysts followed an order of CuOx/TiO2-{001} > CuOx/TiO2-{100} > CuOx/TiO2-{101}. TiO2 facets were found to strongly affect the CuOx-TiO2 interaction and structures of CuOx/TiO2 photocatalysts. Cu2O-TiO2 interaction in CuOx/TiO2-{001} photocatalyst is the strongest, resulting in the highest Cu2O dispersion and density of Cu2O-TiO2 heterojunctions active in photocatalytic H2 production. The results add insights into morphology engineering as an effective strategy to tune structures and photocatalytic activity of TiO2-based composite photocatalysts.
关键词： metal-support interaction,water reduction,charge separation,photocatalysis,facet
更新于2025-09-04 15:30:14
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Enhancing Solar‐Driven Water Splitting with Surface‐Engineered Nanostructures
摘要： Functional nanoscale interfaces that promote the transport of photoexcited charge carriers are fundamental to efficient hydrogen production during photoelectrochemical (PEC) splitting of water. Here, the realization of a functional one-dimensional nanostructure achieved through surface engineering of hematite (α-Fe2O3) nanorods with a TiO2 overlayer is reported. The surface-engineered hematite nanostructure exhibits significantly improved PEC performance as compared to untreated α-Fe2O3, with an increase in the maximum incident photon-to-current efficiency (IPCE) of nearly 400% at 350 nm. While addition of the TiO2 overlayer did not alter the lifetime of photoexcited charge carriers, as evidenced from transient absorption spectroscopy, it is found that the presence of TiO2 could enhance oxygen electrocatalysis by interfacial electron enrichment, largely attributed to enhanced O(2p)(cid:1)Fe(3d) hybridization. Moreover, the interfacial electronic structure revealed from XANES measurements of the α-Fe2O3/TiO2 nanorods suggests that photoexcited holes in α-Fe2O3 may efficiently transfer through the TiO2 overlayer to the electrolyte while electrons migrate to the external circuit along the one-dimensional nanorods, thereby promoting charge separation and enhancing PEC splitting of water.
关键词： photoelectrochemical water splitting,titania,surface engineering,hematite,nanostructure
更新于2025-09-04 15:30:14
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Highly efficient multifunctional Ag/TiO2 nanotubes/Ti plate coated with MIL-88B(Fe) as a photocatalyst, adsorbent, and disinfectant in water treatment
摘要： Multifunctional MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plates were prepared via dip-coating process. Pollutant removals from aqueous solutions were investigated using three different reactions: (1) adsorption of heavy metal ion (Pb2+ and Cd2+), (2) photocatalytic degradation of methyl orange dye (MO), and (3) antibacterial effect for Escherichia coli (E. coli) degradation. Photocatalytic results for dye degradation under UV light irradiation proved the highest activity of the MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plates. The degradation rate constant of MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plates was approximately four times as that of pure TiO2 nanotubes/Ti under UV irradiation. In addition, this plate showed the effective removal of heavy metal ions by sorption process. The adsorption of Pb2+ and Cd2+on the MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plates reached a maximum capacity of 113 and 138 mg/g, and this value was approximately 1.6 times as that of pure TiO2 nanotubes/Ti. In addition, the multifunctional composite plates demonstrated great antibacterial activities towards E. coli. All bacteria colonies killed after 60 min photocatalytic treatment on MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plates. The results show the importance of a cooperative effect between the MIL-88B(Fe) metal organic framework (MOF) and Ag/TiO2 nanotubes/Ti plates. The simultaneous removals of these pollutants with the high efficiency showed an facile approach for the polluted water treatment via the newly fabricated MIL-88B(Fe)–Ag/TiO2 nanotubes/Ti plate with multiple functions.
关键词： Photocatalyst,Ag/TiO2 nanotubes/Ti,MIL-88B(Fe),Water treatment,Disinfectant,Adsorbent
更新于2025-09-04 15:30:14
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Band structure tuning and charge separation of MNX monolayers and MNX/GaS van der Waals heterostructures
摘要： Efficient charge separation and band structure tuning are very important for application to photoelectric device. Here, based on first-principles calculations, we propose two-dimensional (2D) MNX (M=Zr, Hf; X=Cl, Br, I) monolayers which can be exfoliated from the corresponding layered bulk phase due to the low cleavage energy. The phonon band structure and the mechanical analysis indicate that 2D MNX monolayers can form free-standing membranes. The calculated results suggest that 2D MNX monolayers are indirect band gap semiconductors with band gaps in the range of 1.55-3.37 eV. Among them, MNI (M=Zr, Hf) monolayers with effective charge separation and moderate band gaps would have potential application to photocatalytic water splitting. In order to realize the effective charge separation for the other MNX monolayers, MNX/GaS (X=Cl, Br) heterostructures are investigated. Our calculations reveal that MNX/GaS heterostructures are typical type-II band alignment, facilitating the separation of photogenerated carriers where electrons and holes are localized in MNX and GaS monolayers, respectively. Furthermore, the band gaps of the MNX/GaS heterostructures are obviously narrowed compared to those of the isolated constituent monolayers. In addition, the band gaps and band edge positions of MNX/GaS heterostructures can further be tuned by biaxial strain to match better with the redox potentials of water. These findings in this study not only enrich the family of 2D materials, but also demonstrate that MNI (M=Zr, Hf) monolayers and MNX/GaS heterostructures are promising candidates for photocatalytic materials.
关键词： van der Waals heterostructures,photocatalytic water splitting,band structure tuning,MNX monolayers,charge separation
更新于2025-09-04 15:30:14
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The Middle Road Less Taken: Electronic-Structure-Inspired Design of Hybrid Photocatalytic Platforms for Solar Fuel Generation
摘要： The development of efficient solar energy conversion to augment other renewable energy approaches is one of the grand challenges of our time. Water splitting, or the disproportionation of H2O into energy-dense fuels, H2 and O2, is undoubtedly a promising strategy. Solar water splitting involves the concerted transfer of four electrons and four protons, which requires the synergistic operation of solar light harvesting, charge separation, mass and charge transport, and redox catalysis processes. It is unlikely that individual materials can mediate the entire sequence of charge and mass transport as well as energy conversion processes necessary for photocatalytic water splitting. An alternative approach, emulating the functioning of photosynthetic systems, involves the utilization of hybrid systems wherein different components perform the various functions required for solar water splitting. The design of such hybrid systems requires the multiple components to operate in lockstep with optimal thermodynamic driving forces and interfacial charge transfer kinetics.
关键词： hybrid systems,water splitting,photocatalytic,charge transfer,solar energy conversion
更新于2025-09-04 15:30:14