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Sustainable Recovery of CO2 by Using Visible-Light-Responsive Crystal Cuprous Oxide/Reduced Graphene Oxide
摘要： A simple solution-chemistry method has been investigated to prepare crystal cuprous oxide (Cu2O) incorporated with reduced graphene oxide (designated as Cu2O-rGO-x, where x represents the contents of rGO = 1%, 5% and 10%) in this work. These Cu2O-rGO-x composites combine the prospective advantages of rhombic dodecahedra Cu2O together with rGO nanosheets which have been studied as visible-light-sensitive catalysts for the photocatalytic production of methanol from CO2. Among the Cu2O-rGO-x photocatalysts, the methanol yield photocatalyzed by Cu2O-rGO-5% can be observed to be 355.26 μmol g?1cat, which is ca. 36 times higher than that of pristine Cu2O nanocrystal in the 20th hour under visible light irradiation. The improved activity may be attributed to the enhanced absorption ability of visible light, the superior separation of electron–hole pairs, well-dispersed Cu2O nanocrystals and the increased photostability of Cu2O, which are evidenced by employing UV-vis diffuse reflection spectroscopy, photoluminescence, scanning electron microscopy/transmission electron microscopy and X-ray photoelectron spectroscopy, respectively. This work demonstrates an easy and cost-effective route to prepare non-noble photocatalysts for efficient CO2 recovery in artificial photosynthesis.
关键词： cuprous oxide,solar energy,visible-light-driven,graphene,CO2 conversion
更新于2025-09-23 15:22:29
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AgCl/Ag/LaFeO3 heterojunction with a prolonged charge lifetime and enhanced visible light catalytic property
摘要： In this study, uniform mesoporous three–dimensional LaFeO3 with diameter of 2–3 μm was prepared by a hydrothermal process and monodispersed AgCl was then decorated on the surface of the LaFeO3 to form AgCl/Ag/LaFeO3 heterojunction via a facile precipitation–deposition process. The e?ects of the proportions employed in the preparation of the heterojunction on the structural, crystallinity, surface areas, and optical properties of AgCl/Ag/LaFeO3 were systematically studied, which showed that the AgCl/Ag/LaFeO3 heterojunction had a strong hybrid–junction structure, suitable absorption edge, and many exposed surface sites. The AgCl/Ag/LaFeO3 heterojunction had a strong catalytic activity during the degradation of methylene blue and phenol under visible light. The results demonstrated that the AgCl/Ag/LaFeO3 heterojunction had a more intense photocurrent response and smaller surface resistance than both AgCl and LaFeO3. The enhanced photocatalytic ability was attributed to the formation of heterojunctions between AgCl and LaFeO3, which suppressed the recombination of photogenerated electron–hole pairs. Our results may facilitate the rational design of highly e?cient heterogeneous heterojunctions for the removal of organic pollution.
关键词： AgCl/Ag/LaFeO3,Hybrid–junction structure,Charge transfer property,Visible light
更新于2025-09-23 15:22:29
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A Simple Route in Fabricating Carbon-Modified Titania Films with Glucose and Their Visible-Light-Responsive Photocatalytic Activity
摘要： Carbon-modi?ed titania (C–TiO2) ?lms were easily prepared by using an impregnation process with a glucose-containing TiO2 sol. Through controlling calcination conditions, the as-obtained C–TiO2 products exhibited highly photocatalytic activity for the degradation of gaseous NOx under visible light and ultraviolet illumination. The effects of carbon content and calcination temperature on the photocatalytic performances and their photochemical and physical properties were investigated. Carbonaceous species on the TiO2 surface enhanced the visible-light absorption of TiO2 ?lms; however, an excessive amount of carbon on the TiO2 surface reduced its photocatalytic ability due to the serious coverage effect on active sites. The results show that a suitable glucose addition is about 50–100% of the weight of TiO2 content and the optimized calcination temperature is 300 ?C, which leads to better photocatalytic activity under ultraviolet and visible- light irradiations. Accordingly, the simple-prepared C–TiO2 ?lms functioned as visible-light-responsive catalysts, allowing for a feasible producing route for real applications.
关键词： glucose,titania ?lm,impregnation,carbon-modi?ed,visible-light-responsive
更新于2025-09-23 15:22:29
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VLC and D2D Heterogeneous Network Optimization: A Reinforcement Learning Approach Based on Equilibrium Problems with Equilibrium Constraints
摘要： The Radio Frequency (RF) spectrum crunch has triggered the harnessing of other sources of bandwidth, for which visible light is a promising candidate. Even though Visible Light Communication (VLC) ensures high capacity, coverage is limited. This necessitates the integration of VLC and Device-to-Device (D2D) technologies into heterogeneous networks. In particular, mobile users which are accessible by the VLC transmitters can relay data to mobile users which are not, by means of D2D communication. However, due to the distributed behaviors of mobile users, determining optimal data transmission routes from VLC transmitters to end mobile devices is a major challenge. In this paper, we propose a Reinforcement Learning (RL) based approach to determine multi-hop data transmission routes in an indoor VLC-D2D heterogeneous network. We obtain the rewards for the RL based method dynamically, by formulating the interactions between the mobile users relaying the data as an Equilibrium Problem with Equilibrium Constraints (EPEC) and using Alternating Direction Method of Multipliers (ADMM) to solve it. The proposed technique can achieve optimal data transmission routes in a distributed manner. Simulation results demonstrate the effectiveness of the proposed approach, showing that transmission routes with low delays and high capacities can be achieved through the learning algorithm.
关键词： Device-to-Device,Reinforcement Learning,Visible Light Communication,Alternating Direction Method of Multipliers,Heterogeneous Network,Equilibrium Problem with Equilibrium Constraints
更新于2025-09-23 15:22:29
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Simplified Vehicle Vibration Modeling for Image Sensor Communication
摘要： Image sensor communication (ISC), derived from visible light communication (VLC) is an attractive solution for outdoor mobile environments, particularly for intelligent transport systems (ITS). In ITS-ISC, tracking a transmitter in the image plane is critical issue since vehicle vibrations make it difficult to select the correct pixels for data reception. Our goal in this study is to develop a precise tracking method. To accomplish this, vehicle vibration modeling and its parameters estimation, i.e., representative frequencies and their amplitudes for inherent vehicle vibration, and the variance of the Gaussian random process representing road surface irregularity, are required. In this paper, we measured actual vehicle vibration in a driving situation and determined parameters based on the frequency characteristics. Then, we demonstrate that vehicle vibration that induces transmitter displacement in an image plane can be modeled by only Gaussian random processes that represent road surface irregularity when a high frame rate (e.g., 1000 fps) image sensor is used as an ISC receiver. The simplified vehicle vibration model and its parameters are evaluated by numerical analysis and experimental measurement and obtained result shows that the proposed model can reproduce the characteristics of the transmitter displacement sufficiently.
关键词： vehicle motion model,vehicle vibration,visible light communication,image sensor communication,road surface irregularity,transmitter displacement
更新于2025-09-23 15:22:29
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Visible-Light-Driven Photocatalytic Z-scheme Overall Water Splitting in La5Ti2AgS5O7-based Powder Suspension System
摘要： La5Ti2CuxAg1-xS5O7 (x=0-1) is a kind of long-wavelength-responsive oxysulfide photocatalysts for hydrogen evolution, and has been demonstrated to enable the Z-scheme water splitting coupling with oxygen evolution photocatalysts (OEP) the particulate sheet. We herein report that among La5Ti2CuxAg1-xS5O7, La5Ti2AgS5O7 was found to have the highest performance on Z-scheme overall water splitting in conjunction with PtOx-WO3 as an OEP, and a triiodide/iodide (I3?/I?) redox couple as a shuttle electron mediator in powder suspension system. Loading Pt/NiS on La5Ti2AgS5O7 benefits the Z-scheme to achieve an apparent quantum yield of 0.12% at 420 nm. The finding in powder suspension system is opposite to the earlier study on photocatalyst sheet configurations in which p-type doping and the formation of a solid solution can effectively enhance the water-splitting activity. This work not only shows a La5Ti2AgS5O7-based Z-scheme water splitting photocatalyst, but also may present a better understanding for the difference between particulate sheet and powder suspension system available in an optimal strategy for water splitting.
关键词： photocatalysis,water splitting,visible light,Z-scheme,oxysulfides
更新于2025-09-23 15:22:29
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Electrochemical synthesis of copper(II) oxide nanorods and their application in photocatalytic reactions
摘要： A new way of synthesizing nanoscale copper oxide particles is described in this work. Oxides of an intermediate metal, such as copper oxide, can be used as an effective semiconductor in the photocatalytic reactions once they are prepared in a special way. The CuO nanorods were synthesized electrochemically under surfactant-free, static conditions. The obtained nanorods have an average length of less than 50 nm. The CuO nanorods were used as a heterogeneous catalyst in an aqueous medium. 2,4-Dichlorophenol (DCP) was used as a probe molecule. The CuO nanorods showed an excellent ability to degrade DCP under visible light and without the need for any auxiliary oxidizing agent.
关键词： CuO,DCP,Visible light,Degradation,Nanorods,Heterogeneous catalyst
更新于2025-09-23 15:22:29
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ZnO/CdS/PbS nanotube arrays with multi-heterojunctions for efficient visible-light-driven photoelectrochemical hydrogen evolution
摘要： High performance, low cost and sustainable photocatalytic evolution of hydrogen is a promising energy supply alternative for modern society to resolve the depletion crisis of fossil fuel. The design of multi-heterojunction visible-light photocatalysts combined with electrochemical means is considered one of the most attractive options in recent years. In this work, a photoanode composed of top-opened ZnO/CdS/PbS nanotube arrays (ZnO/CdS/PbS ONTs) with multi-heterojunctions was synthesized via a three-step process, i.e. hydrothermal treatment, chemical bath deposition and successive ionic layer adsorption reaction (SILAR). This as-prepared photoanode exhibited remarkable photoelectrochemical activity under visible light irradiation. The photocurrent density and photoelectrochemical hydrogen evolution efficiency of the optimized ZnO/CdS/PbS ONTs reached up to 14.2 mA cm-2 and 5.5 mL cm-2 h-1 at 0.0 V vs. Ag/AgCl, respectively. The efficiency was 3.1 times that of top-closed ZnO/CdS nanotubes (1.8 mL cm-2 h-1). The experimental results suggest that the high photoelectrochemical activity can be ascribed to the inherent advantages of the structural and successive energy level relays design: on the one hand, the top-opened nanotube structure significantly enlarges surface area of the nanostructure, which facilitates efficient light absorption and rapid mass transport; on the other hand, the well-matched band energy edge of the multi-heterojunction interfaces literally build efficient electron highways to deliver electrons to reaction sites and reduce the recombination of photogenerated charge carriers.
关键词： CdS,visible light,multi-heterojunction,ZnO,photoelectrochemical hydrogen evolution,PbS
更新于2025-09-23 15:22:29
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Efficient visible-light-responsive photocatalyst: Hybrid TiO2-Ag3PO4 nanorods
摘要： Herein, ordered TiO2-Ag3PO4 nanorods are fabricated by loading Ag3PO4 nanoparticles on the as-prepared brookite TiO2 nanorods. The amount of Ag3PO4 nanoparticles loaded on brookite TiO2 nanorods can be rationally optimized. These hybrid TiO2-Ag3PO4 nanorods could provide large surface area, extend the visible light absorption and facilitate the charge separation, leading to efficient visible-light-driven photocatalytic performance. When evaluated as photocatalysts under visible light illumination, all the hybrid TiO2-Ag3PO4 nanorods exhibit high photocatalytic activity for degrading 2-propanol. Particularly, TiO2-Ag3PO4-3 enables the best photocatalytic property, which yields high acetone production of 147 ppm at 3 h and CO2 production of 424 ppm at 11 h.
关键词： TiO2-Ag3PO4,Visible-light-responsive,Nanocomposites,Solar energy materials
更新于2025-09-23 15:22:29
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Synthesis of C-In2O3/BiOI composite and its enhanced photocatalytic degradation for methyl blue
摘要： In this work, C-In2O3/BiOI composite is synthesized and used as a high performance photocatalyst for photocatalytic degradation of methyl blue (MB) in wastewater. The C-In2O3/BiOI composites demonstrate 5 times higher photocatalytic performance than the pristine BiOI and In2O3 for MB degradation under the irradiation of visible light. Furthermore, the C-In2O3/BiOI composites have excellent cycling stability. Such enhanced photoactivity is due to the significantly enhanced separation efficiency of photogenerated. This work provides some significance in the design and construction of environmentally benign catalysts with excellent photocatalytic degradation of toxic pollutants.
关键词： C-In2O3/BiOI,Methyl blue,Photocatalysis,Visible light
更新于2025-09-23 15:22:29