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- 实验方案
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Noble-metal-free MoS2 nanosheet-coupled MAPbI3 photocatalyst for efficient and stable visible-light-driven hydrogen evolution
摘要： We report that MoS2 nanosheets (MoS2 NSs) as an cocatalyst in situ coupled with MAPbI3 leads to a highly efficient composite photocatalyst for visible-light-driven photocatalytic H2 evolution. The most efficient MAPbI3/MoS2 NSs exhibits a high H2 evolution rate (206.1 μmol h-1) in MAPbI3-saturated HI solution, which is 121 times higher than that of pristine MAPbI3 (1.7 μmol h-1) and greatly superior to that of MAPbI3/Pt/C (68.5 μmol h-1), and the composite is very stable for H2 evolution in 156 h reaction.
关键词： photocatalyst,MoS2 nanosheets,visible-light-driven,MAPbI3,hydrogen evolution
更新于2025-09-19 17:13:59
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Direct growth of high-content 1T phase MoS2 film by pulsed laser deposition for hydrogen evolution reaction
摘要： The modified MoS2-based material, with a higher conductivity and rich active sites, is promising one of a variety of nonprecious-metal electrocatalysts for hydrogen evolution reaction (HER). Here, the bulk MoS2 is exfoliated to form small-size MoS2 clusters by pulse laser, which are diluted in solid sulfur and further to form porous film. The 1T phase MoS2 ratio in the prepared film was modulated by adding the different content of sulfur into MoS2 target. Besides, this addition also has an effect on the pore structure of films. Finally, the obtained high-content 1T phase MoS2 film provides the highly metallic conductivity and more active sites, which results in the more enhanced HER catalytic activity with a lower Tafel slope of 38 mV dec-1, a smaller overpotential of 151 mV at 10 mA cm-2, compared with the pure MoS2 film.
关键词： pulsed laser deposition,sulfur addition,1T phase MoS2,Hydrogen evolution reaction
更新于2025-09-19 17:13:59
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Controlled Growth and Bandstructure Properties of One Dimensional Cadmium Sulfide Nanorods for Visible Photocatalytic Hydrogen Evolution Reaction
摘要： One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H2). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication of highly efficient photocatalysts. Herein, 1D CdS nanorods (NRs) were synthesized by a facile and low-cost solvothermal method, in which reaction time played a significant role for increasing the length of CdS NRs from 100 nm to several micrometers. It is confirmed that as the length of CdS NR increases, the visible photocatalytic H2 evolution activity also increases and the CdS NR sample obtained at 18 hr. reaction time exhibited the highest H2 evolution activity of 206.07 μmol.g-1.h-1. The higher H2 evolution activity is explained by the improved optical absorption properties, enhanced electronic bandstructure and decreased electron-hole recombination rate.
关键词： photocatalytic H2 evolution,bandstructure,CdS nanorods,electron-hole recombination,solvothermal synthesis
更新于2025-09-19 17:13:59
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Photocatalysts for Hydrogen Evolution Coupled with Production of Valuea??Added Chemicals
摘要： The conversion of water into clean hydrogen fuel using renewable solar energy can potentially be used to address global energy and environmental issues. However, conventional photocatalytic H2 evolution from water splitting has low efficiency and poor stability. Hole scavengers are therefore added to boost separation efficiency of photoexcited electron–hole pairs and improve stability by consuming the strongly oxidative photoexcited holes. The drawbacks of this approach are increased cost and production of waste. Recently, researchers have reported the use of abundantly available hole scavengers, including biomass, biomass-derived intermediates, plastic wastes, and a range of alcohols for H2 evolution, coupled with value-added chemicals production using semiconductor-based photocatalysts. It is timely, therefore, to comprehensively summarize the properties, performances, and mechanisms of these photocatalysts, and critically review recent advances, challenges, and opportunities in this emerging area. Herein, this paper: 1) outlines reaction mechanisms of photocatalysts for H2 evolution coupled with selective oxidation, C–H activation and C–C coupling, together with nonselective oxidation, using hole-scavengers; 2) introduces equations to compute conversion/selectivity of selective oxidation; 3) summarizes and critically compares recently reported photocatalysts with particular emphasis on correlation between physicochemical characteristics and performances, together with photocatalytic mechanisms, and; 4) appraises current advances and challenges.
关键词： C–C coupling,C–H activation,selective oxidation,photocatalysis,hydrogen evolution
更新于2025-09-19 17:13:59
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Self-Assembled Amphiphilic Molecules for Highly Efficient Photocatalytic Hydrogen Evolution From Water
摘要： Self-assembled molecules for outstanding hydrogen evolution rate and durability should promise practical water splitting due to the versatile visible light absorption, low production cost and ease of control. Here, we adapted an amphiphilic molecule as a building block for efficient small molecule based self-assembled photocatalyst for hydrogen evolution from water. The self-assembled molecules with platinum co-catalyst showed outstanding performance (turnover number ~ 27,000) virtually comparable to the state-of-the-art metal oxide based photocatalysts with catalytic activity extending over days. Transient absorption studies in combination with quantum chemical calculations revealed that elaborate excited state engineering of the molecules resulted in such high performance of hydrogen evolution from water. This study shows that the self-assembled amphiphilic molecules could pave the way to more economical and reproducible production of hydrogen from water.
关键词： Platinum co-catalyst,Amphiphilic molecule,Photocatalytic hydrogen evolution,Excited state engineering,Self-assembled molecules
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Multiple Round-Trip Delay-Based Architecture for Si-Integrated Photonic Reservoir Computing
摘要： This paper presents a cooperative differential evolution (DE) with multiple populations for multiobjective optimization. The proposed algorithm has M single-objective optimization subpopulations and an archive population for an M-objective optimization problem. An adaptive DE is applied to each subpopulation to optimize the corresponding objective of the multiobjective optimization problem (MOP). The archive population is also optimized by an adaptive DE. The archive population is used not only to maintain all nondominated solutions found so far but also to guide each subpopulation to search along the whole Pareto front. These (M + 1) populations cooperate to optimize all objectives of the MOP by using adaptive DEs. Simulation results on benchmark problems with two, three, and many objectives show that the proposed algorithm is better than some state-of-the-art multiobjective DE algorithms and other popular multiobjective evolutionary algorithms. The online search behavior and parameter sensitivity of the proposed algorithm are also investigated.
关键词： Archive,differential evolution (DE),cooperative populations,search,multiobjective optimization,many-objective optimization
更新于2025-09-19 17:13:59
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Electron selective contact for high efficiency core-shell nanowire solar cell
摘要： Self-healing networks aim to detect cells with service degradation, identify the fault cause of their problem, and execute compensation and repair actions. The development of this type of automatic system presents several challenges to be confronted. The first challenge is the scarce number of historically reported faults, which greatly complicates the evaluation of novel self-healing techniques. For this reason, in this paper, a system model to simulate faults in Long-Term Evolution (LTE) networks, along with their most significant key performance indicators, is proposed. Second, the expert knowledge required to build a self-healing system is usually not documented. Therefore, in this paper, a methodology to extract this information from a collection of reported cases is proposed. Finally, following the proposed methodology, an automatic fuzzy-logic-based system for fault identification in LTE networks is designed. Evaluation results show that the fuzzy system provides fault identification with a high success rate.
关键词： Long-Term Evolution (LTE),Diagnosis,fuzzy logic,fault identification,troubleshooting,root cause analysis,self-healing,fault management
更新于2025-09-19 17:13:59
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High Sensitivity Terahertz Biosensor Based on Goos-H?¤nchen Effect in Graphene
摘要： Low-density parity-check (LDPC) codes with very long block lengths are well known for their powerful error correction, but it is not always desirable to employ long codes in communication systems, where latency is a serious issue, such as voice and video communication between multiple users. Finite length analyses of LDPC codes have already been presented in the literature for the additive white Gaussian noise channel, but in this paper, we consider the finite length analysis of LDPC codes for channels that exhibit impulsive noise. First, an exact uncoded bit error probability (BEP) of an impulsive noise channel, modeled as a symmetric α-stable (SαS) distribution, is derived. Then, to obtain the LDPC-coded performance, density evolution is applied to evaluate the asymptotic performance of LDPC codes on SαS channels and determine the threshold signal-to-noise ratio. Finally, we derive closed-form expressions for the BEP and block error probability of short LDPC codes on these channels, which are shown to match closely with simulated results on channels with different levels of impulsiveness, even for block lengths as low as 1000 b.
关键词： impulsive noise,density evolution,finite length analysis,LDPC codes
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - High Throughput Detection of Cracks and Other Faults in Solar PV Modules Using a High-Power Ultraviolet Fluorescence Imaging System
摘要： Low-density parity-check (LDPC) codes with very long block lengths are well known for their powerful error correction, but it is not always desirable to employ long codes in communication systems, where latency is a serious issue, such as voice and video communication between multiple users. Finite length analyses of LDPC codes have already been presented in the literature for the additive white Gaussian noise channel, but in this paper, we consider the finite length analysis of LDPC codes for channels that exhibit impulsive noise. First, an exact uncoded bit error probability (BEP) of an impulsive noise channel, modeled as a symmetric α-stable (SαS) distribution, is derived. Then, to obtain the LDPC-coded performance, density evolution is applied to evaluate the asymptotic performance of LDPC codes on SαS channels and determine the threshold signal-to-noise ratio. Finally, we derive closed-form expressions for the BEP and block error probability of short LDPC codes on these channels, which are shown to match closely with simulated results on channels with different levels of impulsiveness, even for block lengths as low as 1000 b.
关键词： impulsive noise,density evolution,finite length analysis,LDPC codes
更新于2025-09-19 17:13:59
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Spectral tuning mediated by helix III in butterfly long wavelength-sensitive visual opsins revealed by heterologous action spectroscopy
摘要： Absorption spectra of opsin-based pigments are tuned from the UV to the red regions by interactions of the chromophore with surrounding amino acid residues. Both vertebrates and invertebrates possess long-wavelength-sensitive (LWS) opsins, which underlie color vision involving “red” sensing. The LWS opsins have independently evolved in each lineage, which suggests the existence of diverse mechanisms in spectral tuning. In vertebrate LWS opsins, the mechanisms underlying spectral tuning have been well characterized by spectroscopic analyses with recombinant pigments of wild type (WT) and mutant opsins. However in invertebrate LWS opsins including insect ones, the mechanisms are largely unknown due to the difficulty in obtaining recombinant pigments. Here we have overcome the problem by analyzing heterologous action spectra based on light-dependent changes in the second messenger in opsin-expressing cultured cells. We found that WTs of two LWS opsins of the butterfly, Papilio xuthus, PxRh3 and PxRh1 have the wavelengths of the absorption maxima at around 570 nm and 540 nm, respectively. Analysis of a series of chimeric mutants showed that helix III is crucial to generating a difference of about 15 nm in the wavelength of absorption maxima of these LWS opsins. Further site-directed mutations in helix III revealed that amino acid residues at position 116 and 120 (bovine rhodopsin numbering system) are involved in the spectral tuning of PxRh1 and PxRh3, suggesting a different spectral tuning mechanism from that of primate LWS opsins.
关键词： Red sensitivity,Rhodopsin,Color vision,Convergent evolution
更新于2025-09-19 17:13:59