- 标题
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Analysis of CO2 emission reduction contribution and efficiency of Chinaa??s solar photovoltaic industry: Based on Input-output perspective
摘要： As one of the most promising renewable energy sources, the amount of solar photovoltaics has reached 104.1 GW in 2018. China not only has the natural advantages of abundant solar energy resources, but the photovoltaic industry under the government’s support has also become the main driving force for global development. Facing the structural adjustment of solar photovoltaic parity online and the important contribution of solar power generation to energy conservation and emission reduction, this paper based on the radial and non-radial comprehensive consideration of EBM (Epsilon-Based Measure) DEA (Data envelopment analysis) model from the input-output perspective on solar photovoltaic industry CO2 emission reduction and ef?ciency analyze. It is concluded that the total ef?ciency of the solar photovoltaic industry in China’s six regions shows a growing trend, but the regional differences are obvious. The overall ef?ciency of the northwest region is superior. Among the index ef?ciency, CO2 emission reduction ef?ciency is better than cumulative installed capacity ef?ciency, solar energy utilization hour ef?ciency is the lowest, and CO2 emission reduction and cumulative installed capacity ef?ciency all show a consistent trend. It shows that the ef?ciency of cumulative installed capacity has a positive impact on CO2 emission reduction, but the ef?ciency of solar power generation needs to be improved.
关键词： Ef?ciency evaluation,Input-output,CO2 emission reduction,Solar photovoltaic
更新于2025-09-23 15:21:01
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Hierarchical 3D VO2/ZnV2O4 microspheres as an excellent visible light photocatalyst for CO2 reduction to solar fuels
摘要： The photocatalytic reduction of CO2 has a great potential to produce fuels and chemicals, as well as, it reduces CO2 emission and addresses the environmental issues. To date single metal based catalysts still su?er from lower e?ciency, uncontrollable selectivity and instability. In this study, hierarchical microspheres (HMs) of ZnV2O4 with VO2 impurity were synthesized through the single step reduction process, to explore highly e?cient photocatalyst towards visible light responsive photocatalytic CO2 reduction. HMs of ZnV2O4 were successfully synthesized with mesoporous structure, higher surface area and functional under visible light irradiations. The ?1 were obtained over ZnV2O4 synthesized after highest yield of CO and CH3OH of 378 and 202 μmole g-cat 24 h of reaction time, respectively. The performance of optimized 3D HMs of ZnV2O4 for CO and CH3OH pro-duction was 2.30 folds and 10.7 folds higher than using ZnO/V2O5 composite sample, respectively. Other products detected with appreciable amounts were CH4 and C2H6. This reveals, HMs structure of ZnV2O4 not only allows the transfer of electrons towards CO2, but also provides short pathways for electron transfer and empty space in the microspheres will serve as the reservoirs to store the electrons, hence leading to enhanced photo-activity. In addition, VO2 presents in the sample further contribute to enhance performance of ZnV2O4 HMs due to enabling e?cient charge carrier separation. The prolong stability of ZnV2O4 in the CO2 reduction system con?rmed that 3D HMs structure provides controllable selectivity and stability. This brings to conclusions that fabrication of hierarchical structures will stimulate further development towards high performance photo-cat-alysts for the photocatalytic CO2 reduction to solar hydrocarbon fuels.
关键词： Hierarchical structure,CO2 reduction,Ternary metal oxide,Zinc vanadium oxide,3D microspheres of ZnV2O4,Hydrocarbon fuels
更新于2025-09-23 15:21:01
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Origin of the Overpotential for the Oxygen Evolution Reaction on a Well-defined Graphene Electrode Probed by in situ Sum Frequency Generation Vibrational Spectroscopy
摘要： To develop an efficient material for the cathode of the lithium-oxygen (Li-O2) secondary battery, the oxygen reduction and evolution reactions (ORR and OER) on a well-defined graphene monolayer have been investigated in a typical organic solvent, dimethyl sulfoxide (DMSO). The adsorption and desorption behaviors of the solvents on the graphene electrode surface were evaluated by an intrinsically surface-selective vibrational spectroscopy of sum frequency generation (SFG) during the ORR and OER. After the initial ORR depositing lithium peroxide (Li2O2) on the graphene electrode surface in a LiClO4/DMSO solution, the SFG spectroscopy revealed that the subsequent OER oxidizing the Li2O2 preferentially proceeds at the interface between the Li2O2 and graphene rather than that between the Li2O2 and bulk solution. Therefore, the OER tends to reduce the electric conductivity between the Li2O2 and graphene by decreasing their contact area before a large part of the deposited Li2O2 was oxidized, which elucidates the origin of the high overpotential for the OER.
关键词： oxygen reduction reaction,lithium-oxygen battery,oxygen evolution reaction,sum frequency generation vibrational spectroscopy,graphene electrode
更新于2025-09-23 15:21:01
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Why and how carbon dioxide conversion to methanol happens on functionalized semiconductor photoelectrodes
摘要： Functionalization of semiconductor electrode surfaces with adsorbed 2-pyridinide (2-PyH–*) has been postulated to enable selective CO2 photo-electro-reduction to CH3OH. This hypothesis is supported by recent estimates of sufficient 2-PyH–* lifetimes and low barriers for hydride transfer (HT) to CO2. However, the complete mechanism for reducing CO2 to CH3OH remained unidentified. Here, vetted quantum chemistry protocols for modeling GaP reveal a pathway involving HTs to specific CO2 reduction intermediates. Predicted barriers suggest that HT to HCOOH requires adsorbed HCOOH* reacting with 2-PyH–*, a new catalytic role for the surface. HT to HCOOH* produces CH2(OH)2 but subsequent HT to CH2(OH)2 forming CH3OH is hindered. However, CH2O, dehydrated CH2(OH)2, easily reacts with 2-PyH–* producing CH3OH. Further reduction of CH3OH to CH4 via HT from 2-PyH–* encounters a high barrier, consistent with experiment. Our finding that the GaP surface enables HT to HCOOH* explains why the primary CO2 reduction product over CdTe photoelectrodes is HCOOH rather than methanol, as HCOOH does not adsorb on CdTe and so the reaction terminates. The stability of 2-PyH–* (vs. its protonation product DHP*), the relative dominance of CH2(OH)2 over CH2O, and the required desorption of CH2(OH)2* are the most likely limiting factors, explaining the low yield of CH3OH observed experimentally.
关键词： hydride transfer,CO2 reduction,semiconductor,photoelectrodes,methanol
更新于2025-09-23 15:21:01
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Design and adaptability of photovoltaic air conditioning system based on office buildings
摘要： Photovoltaic (PV) air conditioning (AC) is an effective way to solve the problems of energy consumption of office buildings. In this study, a set of parameters were designed for PV AC, including PV capacity, AC parameter, and inverter parameter. Then, the parameters were applied to a 20-m2 office building, and a PV AC system test platform was built. The test lasted for one year; the corresponding data including typical daily data and annual data were collected and analyzed. The results show that the PV AC system quickly decreases or increases the room temperature by ~9.5% and 17% in 1 h of cooling and heating periods, respectively, thus maintaining the room temperature within the set temperature range of ± 0.9 °C. The data also show that by proper design of parameters, a PV AC system can satisfy the electricity demand of AC. In the cooling period, heating period, and annual operation conditions, the PV system provided 114%, 73%, and 188% of the energy for the AC system, respectively. Next, economic calculations show that PV AC is suitable for office buildings. The local payback period is only 7.5 years; both the energy saving and emission reduction are significant.
关键词： Energy saving,Design of parameters,Office buildings,Photovoltaic air conditioning,Emission reduction
更新于2025-09-23 15:21:01
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Macro Pixel ASIC (MPA): the readout ASIC for the pixel-strip (PS) module of the CMS outer tracker at HL-LHC
摘要： The CMS tracker at HL-LHC is required to provide prompt information on particles with high transverse momentum to the central Level 1 trigger. For this purpose, the innermost part of the outer tracker is based on a combination of a pixelated sensor with a short strip sensor, the so-called Pixel-Strip module (PS). The readout of these sensors is carried out by distinct ASICs, the Strip Sensor ASIC (SSA), for the strip layer, and the Macro Pixel ASIC (MPA) for the pixel layer. The processing of the data directly on the front-end module represents a design challenge due to the large data volume (30720 pixels and 1920 strips per module) and the limited power budget. This is the reason why several studies have been carried out to ?nd the best compromise between ASICs performance and power consumption. This paper describes the current status of the MPA ASIC development where the logic for generating prompt information on particles with high transverse momentum is implemented. An overview of the readout method is presented with particular attention on the cluster reduction, position encoding and momentum discrimination logic. Concerning the architectural studies, a software test bench capable of reading physics Monte-Carlo generated events has been developed and used to validate the MPA design and to evaluate the MPA performance. The MPA-Light is scheduled to be submitted for fabrication this year and will include the full analog functions and a part of the digital logic of the ?nal version in order to qualify the chosen VLSI technology for the analog front-end, the module assembly and the low voltage digital supply.
关键词： Digital electronic circuits,Data reduction methods,Pixelated detectors and associated VLSI electronics
更新于2025-09-23 15:21:01
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Carbon Vacancies in a Melon Polymeric Matrix Promote Photocatalytic Carbon Dioxide Conversion
摘要： Photosynthetic conversion CO2 into fuel and chemicals is a promising but challenging technology. The bottleneck of this reaction lies in the activation of CO2, owing to the chemical inertness of linear CO2. Herein, we present a defect engineering methodology to construct CO2 activation sites by implanting carbon vacancies (CVs) on the melon polymer (MP) matrix. Positron annihilation spectroscopy confirms the location and density of the CVs in the MP skeleton. transform spectroscopy and density functional theory (DFT) study reveals that the CVs can function as active sites for CO2 activation, while stabilizing COOH* intermediates, thereby boosting the reaction kinetics. As a result, the modified MP-TAP-CVs display a 45-fold improvement in CO2-to-CO activity over the pristine MP. The apparent quantum efficiency of the MP-TAP-CVs achieves 4.8 % at 420 nm, which exceeds most of the heterogeneous reduction of CO2 under visible light. This study will shed new light on the design of high-efficiency polymer semiconductors for CO2 conversion.
关键词： Carbon nitride,Photocatalysis,CO2 reduction,Carbon vacancy
更新于2025-09-23 15:21:01
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Peripherally functionalized based dendrimers as the template for synthesis of silver nanoparticles and investigation the affecting factors on their properties
摘要： Today, dendrimers (D) were introduced as a versatile template for the synthesis of nanoparticles (NPs). In this work, the stable silver nanoparticles (AgNPs) is successfully synthesized through the chemical reduction of AgNO3 using NaBH4 as a reducing agent. Synthesis of AgNPs was performed in the presence of different generations of citric acid-based dendrimers (G1, G2 and G3) and hydroxyl-terminated citric acid-based dendrimers (G1-OH, G2-OH and G3-OH). High-resolution transmission electron microscopy, electron diffraction and energy-dispersive X-ray analysis were used to characterize the synthesized AgNPs. UV–Vis results were used for the qualitative study of the synthesized AgNPs properties. With varying the molar ratio of dendrimer/Ag+, generations of dendrimers and the pH of the solution, the size and size distribution of AgNPs could be easily controlled at room temperature. The average diameter of the synthesized AgNPs in the presence of Gn-OH was in the range of 8–20 nm. Results show that G1-OH alkaline medium with 1:1 molar ratio of D/Ag is the optimum condition for the synthesis of AgNPs. All the obtained results from this study showed that controlling the medium conditions allows AgNPs with the desired size to be obtained.
关键词： Chemical reduction,Silver nanoparticles,Citric acid,Hydroxyl-terminated dendrimer,Dendrimer
更新于2025-09-23 15:21:01
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Study of road tunnel threshold zone lighting reduction coefficient; 公路隧道入口段亮度折减系数研究;
摘要： The luminance in the road tunnel threshold zone attracts broad attention due to its enormous energy consumption and direct influence on tunnel transportation security. Current lighting design methods in threshold zones mostly adopt the reduction coefficient method. However, the determination of reduction coefficient k simply considers tunnel design speed and flow rate, while excluding outside tunnel luminance and threshold zone color temperature and luminance, which have a major impact on driver visual adaptation. Existing problems in the determination of k value are analyzed; a visual performance experiment is utilized; and the reaction time of drivers in changeable outside tunnel luminance and threshold zone color temperature and luminance conditions is obtained; thus, the equations concerning reduction coefficient variation law are derived. In the end, a comparative analysis is made of the k values of the reduction coefficient stipulated by various norms under different color temperature conditions.
关键词： reaction time,threshold zone,visual performance,reduction coefficient,tunnel lighting
更新于2025-09-23 15:21:01
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Effect of TaN intermediate layer on the back contact reaction of sputter-deposited Cu poor Cu2ZnSnS4 and Mo
摘要： Ultrathin tantalum nitride (TaN) intermediate layers (IL) with thicknes from 3 nm to 12 nm have been used to limit the undesirable interfacial reaction between molybdenum (Mo) and copper-zinc-tin-sulphide (CZTS). The morphology, chemical and structural properties of the samples were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction analysis, and scanning transmission electron microscopy (STEM). Time-of-flight secondary ion mass spectrometry (TOFSIMS), energy-dispersive X-ray spectroscopy (EDX), and electron energy loss spectroscopy (EELS) have been used for elemental analysis. Thin TaN IL show chemical reactivity towards sulphur (S) vapor at 600oC and the incorporation of S in TaN reduces the S concentration in Mo films at the sub-surface region and thus improves electrical conductivity of sulphurised Mo. The use of a non-stoichiometric quaternary compound CZTS target along with TaN IL enables to minimise thickness of MoS2 layer and reduce void formation at the Mo/CZTS interface. Furthermore, incorporation of TaN IL improves scratch hardness of CZTS/Mo films to soda-lime glass substrate.
关键词： interface engineering,MoS2,Void reduction,TaN intermediate layer,Elemental out-diffusion,Sputter-grown Cu2ZnSnS4
更新于2025-09-23 15:21:01