- 标题
- 摘要
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- 实验方案
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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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Microwave photonics‐based all optical wavelength conversion of Nyquist‐DP‐16QAM for flex‐grid optical networks with 112 Gbps
摘要： We propose and demonstrate an all optical wavelength conversion of Nyquist differential phase 16 quadrature amplitude modulation based on microwave photonics signal processing for flex-grid optical networks. By analyzing the mechanism of the microwave photonics and the components, multi-adjusting the parameters of wavelength tunable laser with smooth and adjustable optical intensity can be obtained. Then, the multi-channel photonic signals with the minimal guard space of 5 GHz can be obtained, which provide more than 20 flex-grids for optical transmission with transparent rate and format. The optical power of converted wavelengths, optical signal-to-noise ratio, error vector magnitude, and bit error rate (BER) are studied under the condition of different flex-grids, the frequencies of which are from 15 GHz to 36 GHz. The channel frequency spacing and amplitude of the converted wavelength can be dynamically adjusted via parameter configuration. Flex-grid spacing strategies and channel selecting strategies are given. The BER performance of all converted channels can fall below the forward error correction threshold of 3.8 × 10?3 by optimizing the optical power of the receiver end. The results show the tradeoff between the BER and the detected optical power of the receiver end. These research findings could provide solutions for spectrum allocation and routing selection when wavelength conversion is needed in optical links.
关键词： coherent communication,microwave photonics,wavelength conversion,flex-grid optical networks
更新于2025-09-23 15:22:29
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Two-dimensional-related catalytic materials for solar-driven conversion of CO <sub/>x</sub> into valuable chemical feedstocks
摘要： The discovery of improved chemical processes for CO and CO2 hydrogenation to valuable hydrocarbon fuels and alcohols is of paramount importance for the chemical industry. Such technologies have the potential to reduce anthropogenic CO2 emissions by adding value to a waste stream, whilst also reducing our consumption of fossil fuels. Current thermal catalytic technologies available for CO and CO2 hydrogenation are demanding in terms of energy input. Various alternative technologies are now being developed for COx hydrogenation, with solar-driven processes over two-dimensional (2D) and 2D-related composite materials being particularly attractive due to the abundance of solar energy on Earth and also the high selectivity of defect-engineered 2D materials towards specific valuable products under very mild reaction conditions. This review showcases recent advances in the solar-driven COx reduction to hydrocarbons over 2D-based materials. Optimization of 2D catalyst performance demands interdisciplinary research that embraces catalyst electronic structure manipulation and morphology control, surface/interface engineering, reactor engineering and density functional theory modelling studies. Through improved understanding of the structure–performance relationships in 2D-related catalysts which is achievable through the application of modern in situ characterization techniques, practical photo/photothermal/photoelectrochemical technologies for CO and CO2 reduction to high-valuable products such as olefins could be realized in the not-too-distant future.
关键词： hydrocarbons,feedstocks,two-dimensional materials,solar-driven conversion,catalysis,COx reduction
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Vilnius, Lithuania (2018.11.8-2018.11.10)] 2018 IEEE 6th Workshop on Advances in Information, Electronic and Electrical Engineering (AIEEE) - Usage of Signals with a High PAPR Level for Efficient Wireless Power Transfer
摘要： The paper discusses the impact of high-power laser diodes on the conversion efficiency of solar cells in optoelectronics, focusing on the use of specific materials and experimental setups to enhance performance.
关键词： laser diodes,conversion efficiency,materials,optoelectronics,solar cells
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Design of a Novel Broadband Down Conversion Module
摘要： This paper introduces the design of a novel broadband down conversion module. Firstly the design method of interference signal suppression is presented. Through the application of various of filters, all kinds of interference signals are suppressed to some extent, which satisfies the requirements of the whole system requirement against interference.
关键词： down conversion,hairpin filter,anti-jamming
更新于2025-09-23 15:22:29
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Improvement of Conversion Loss of Resistive Mixers Using Bernal-stacked Bilayer Graphene
摘要： In this letter, we present dual-gate Bernal-stacked bilayer graphene FETs which are used for gate-pumped resistive mixers. The results show that conversion loss improves when the device on/off ratio increases. At 2 GHz, a record conversion loss of 12.7 dB has been obtained from 160 nm device among graphene resistive mixers. Furthermore, more than 10 dB change of conversion loss has been obtained by adjusting the electric displacement field by dual-gate voltage. Finally, high-temperature characteristics of this type of graphene mixer exhibit excellent thermal stability with only 2 dB degradation in conversion loss from 300 to 380 K. This result shows the Bernal-stacked bilayer graphene mixer is promising for low-loss and high-temperature radio frequency circuit applications.
关键词： conversion loss,high temperature,bilayer graphene,resistive mixer,FETs
更新于2025-09-23 15:22:29
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Arbitrary Polarization Conversion with a Photonic Crystal Slab
摘要： It is shown that a simple photonic crystal slab structure provides a powerful mechanism for the control of the polarization properties of light. For a lossless system, for a given incident light with any fixed polarization, one can generate arbitrary polarization in the reflected light, as one varies the direction of the incident light. In the lossy system, the capability for arbitrary polarization generation is still preserved for s- or p-polarized incident light. This capability for arbitrary polarization generation closely relates to the nontrivial topological properties of the reflection matrix of the structure and exists over a wide range of frequencies.
关键词： photonic crystals,polarization conversion,Poincaré sphere,Stokes parameters
更新于2025-09-23 15:22:29
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Transparent Ta3N5 Photoanodes for Efficient Oxygen Evolution toward the Development of Tandem Cells
摘要： Photoelectrochemical water splitting is regarded as a promising approach to the production of hydrogen, and the development of efficient photoelectrodes is one aspect of realizing practical systems. In this work, transparent Ta3N5 photoanodes were fabricated on n-type GaN/sapphire substrates to promote O2 evolution in tandem with a photocathode, to realize overall water splitting. Following the incorporation of an underlying GaN layer, a photocurrent of 6.3 mA cm-2 was achieved at 1.23 V vs. a reversible hydrogen electrode. The transparency of Ta3N5 to wavelengths longer than 600 nm allowed incoming solar light to be transmitted to a CuInSe2 (CIS), which absorbs up to 1100 nm. A stand-alone tandem cell with a serially-connected dual-CIS unit terminated with a Pt/Ni electrode was thus constructed for H2 evolution. This tandem cell exhibited a solar-to-hydrogen energy conversion efficiency greater than 7% at the initial stage of the reaction.
关键词： solar energy conversion,photoelectrochemistry,water splitting,photoelectrochemical tandem cell,(oxy)nitrides
更新于2025-09-23 15:22:29
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Effects of Spatial Dispersion in Symmetric and Asymmetric Semiconductor Quantum Wells
摘要： Effects of spatial dispersion in quantum wells are discovered and investigated in detail in reflection experiments. We studied oblique incidence of pure s and p polarized light which has been reflected elliptically polarized. The polarization degree of the reflected light is governed by the in-plane photon momentum which is the distinctive feature of the spatial dispersion effects. The effects of spatial dispersion are allowed by symmetry in inversion-asymmetric systems only. Therefore we investigated bulk-inversion asymmetric ZnSe/ZnMgSSe and structure-asymmetric GaAs/AlGaAs and CdZnTe/CdTe/CdMgTe quantum wells. We studied the reflected light polarization state in the vicinity of the heavy- and light-exciton resonances where the spatial dispersion effects are resonantly enhanced.
关键词： semiconductor quantum wells,light polarization conversion,excitons,spatial dispersion
更新于2025-09-23 15:22:29
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Generalized optimization method for energy conversion and storage efficiency of nanoscale flexible piezoelectric energy harvesters
摘要： The energy conversion and storage efficiency was commonly ignored in experimental studies on nanoscale flexible piezoelectric energy harvesters (PEHs). In this study, we develop a generalized theoretical method to optimize the energy conversion and storage efficiencies of nanoscale flexible PEHs. The results are validated by comparisons with experimental measurements for various ambient excitations. A simple scaling law is established to reveal the intrinsic correlation between the efficiency of energy conversion/storage and various system parameters of the PEHs. For either the energy conversion or storage circuit, the output power density may be maximized by properly designing an intrinsic normalized parameter. Furthermore, we demonstrate that an independent optimization criterion is indispensable for standard storage circuits since including a storage module into the conversion circuit redefines the electromechanical behavior of the PEH system. The results may be used as guidelines for optimizing the energy conversion and storage efficiencies of nanoscale flexible PEHs that have promising applications in harvesting biomechanical energies.
关键词： Scaling law,Optimization,Nanoscale flexible piezoelectric energy harvesters,Energy conversion,Energy storage
更新于2025-09-23 15:22:29