Practical operating flexibility of a bifunctional freestanding membrane for efficient anion exchange membrane water electrolysis across all current ranges

This study explores a symmetric configuration approach in anion exchange membrane(AEM)water electrolysis,focusing on overcoming adaptability challenges in dynamic conditions.Here,a rapid and mild synthesis technique for fabricating fibrous membrane-type catalyst electrodes is developed.Our method leverages the contrasting oxidation states between the sulfur-doped NiFe(OH)2 shell and the metallic Ni core,as revealed by electron energy loss spectroscopy.Theoretical evaluations confirm that the S–NiFe(OH)_(2) active sites optimize free energy for alkaline water electrolysis intermediates.This technique bypasses traditional energy-intensive processes,achieving superior bifunctional activity beyond current benchmarks.The symmetric AEM water electrolyzer demonstrates a current density of 2 A cm^(-2) at 1.78 V at 60℃ in 1 M KOH electrolyte and also sustains ampere-scale water electrolysis below 2.0 V for 140 h even in ambient conditions.These results highlight the system's operational flexibility and structural stability,marking a significant advance-ment in AEM water electrolysis technology.

Experimental and computational optimization of Prussian blue analogues as high-performance cathodes for sodium-ion batteries:A review

In this review,we discuss the electrochemical properties of Prussian blue(PB)for Na^(+)storage by combining structural engineering and electrolyte modifications.We integrated experimental data and density functional theory(DFT)in sodium-ion battery(SIB)research to refine the atomic arrangements and crystal lattices and introduce substitutions and dopants.These changes affect the lattice stability,intercalation,electronic and ionic conductivities,and electrochemical performance.We unraveled the intricate structure-electrochemical behavior relationship by combining experimental data with computational models,including first-principles calculations.This holistic approach identified techniques for optimizing PB and Prussian blue analog(PBA)structu ral properties for SIBs.We also discuss the tuning of electrolytes by systematically adjusting their composition,concentration,and additives using a combination of molecular dynamics(MD)simulations and DFT computations.Our review offers a comprehensive assessment of strategies for enhancing the electrochemical properties of PB and PBAs through structural engineering and electrolyte modifications,combining experimental insights with advanced computational simulations,and paving the way for next-generation energy storage systems.

Amorphous BaTiO_(3) Electron Transport Layer for Thermal Equilibrium-Governed γ-CsPbl_(3) Perovskite Solar Cell with High Power Conversion Efficiency of 19.96%

Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress.Nonetheless,additional research is required to reduce the nonradiative recombination to realize the full potential of CsPbI_(3).Here,the diffusion of Cs ions participating in ion exchange is proposed to be an important factor responsible for the bulk defects inγ-CsPbI_(3)perovskite.Calculations based on first-principles density functional theory reveal that the[PbI_(6)]^(4-)octahedral tilt modifies the perovskite crystallographic properties inγ-CsPbI_(3),leading to alterations in its bandgap and crystal strain.In addition,by substituting amorphous barium titanium oxide(a-BaTiO_(3))for TiO_(2)as the electron transport layer,interfacial defects caused by imperfect energy levels between the electron transport layer and perovskite are reduced.High-resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that a-BaTiO_(3)forms entirely as a single phase,as opposed to Ba-doped TiO_(2)hybrid nanoclusters or separate domains of TiO_(2)and BaTiO_(3)phases.Accordingly,inorganic perovskite solar cells based on the a-BaTiO_(3)electron transport layer achieved a power conversion efficiency of 19.96%.

孔有效利用的活性炭基非对称电极膜/电容脱盐系统(英文)

采用活性炭纤维为原料制备出膜/电容脱盐系统,提纯含氯化钠的水。OG系列活性炭纤维作为电极的活性材料,其比表面积和孔分布不同而呈现不同的活化程度。将这些材料用于膜/电容脱盐系统,评价了他们对钠离子或氯离子的脱盐性能。膜/电容实验在不同操作电位窗口、含盐溶液的进料速率和浓度下进行。OG系列活性炭纤维对每种离子的脱盐效率和电吸附量来评价膜/电容性能。结果表明,BET比表面积是确保高性能的必要因素。另外,炭材料最上端的浅孔有助于活性炭纤维比表面积的充分利用。OG7A样品的孔结构适合于钠离子吸附,OG10A和OG15A适于大量孔吸附氯离子。因此,非对称电极排列施加于吸附离子的尺寸,应考虑炭材料比表面积和孔面积的有效利用,以得到高性能的膜/电容脱盐系统。

A MoS_2 nanocatalyst with surface-enriched active sites for the heterogeneous transfer hydrogenation of nitroarenes

A highly efficient and reusable plane‐curved and interlayer‐expanded MoS2nanocatalyst with increased exposure of active sites was prepared.The catalyst was used for the heterogeneous hydrogen transfer reaction of nitroarenes with hydrazine monohydrate as a reductant under mild reaction conditions without pressure and base,which was different from other hydrogen transfer systems that require the presence of a base(e.g.,propan‐2‐ol/KOH).The sandwiching of carbon between the MoS2nanosheets increased the distance between the layers of MoS2and exposed more Mo sites,resulting in superior catalytic performance compared with that of bulk MoS2catalyst.The active hydrogen(H*)generated from N2H4could directly transfer to the–NO2groups of nitrobenzene to form aniline followed by N2emission,which was confirmed by detecting the gas emission with mass spectrometry during the decomposition of hydrazine or the co‐existence of nitrobenzene and hydrazine.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

Investigation of thermochemical process of coal particle packed bed reactions for the development of UCG

In this study,a packed bed reactor was developed to investigate the gasification process of coal particles.The effects of coal particle size and heater temperature of reactor were examined to identify the thermochemical processes through the packed bed.Three different coal samples with varying size,named as A,B,and C,are used,and the experimental results show that the packed bed with smaller coal size has higher temperature,reaching 624°C,582°C,and 569°C for coal A,B,and C,respectively.In the case of CO formation,the smaller particle size has greater products in the unit of mole fraction over the area of generation.However,the variation in the porosity of the packed bed due to different coal particle sizes affects the reactions through the oxygen access.Consequently,the CO formation is least from the coal packed bed formed by the smallest particle size A.A second test with the temperature variations shows that the higher heater temperature promotes the chemical reactions,resulting in the increased gas products.The findings indicate the important role of coal seam porosity in underground coal gasification application,as well as temperature to promote the syngas productions.

Self‑Powered Airflow Sensor Based on Energy Harvesting of Ventilation Air in Buildings

Heating,ventilation,and air conditioning(HVAC)systems account for one-third of the total energy consumption in office buildings.The use of airflow measurements to control the operation of HVAC systems can reduce energy consumption;thus,a sensor capable of monitoring airflow in a duct system is critical.Triboelectric nanogenerators(TENGs)can be utilized as self-powered sensors in airflow-driven TENGs(ATENGs)as self-powered sensors.By employing ferroelectric materials and surface modifications,the surface charges of TENGs can be increased.In this study,fibrous-mat TENGs were prepared using ferroelectric materials consisting of poly(vinylidene fluoride-co-trifluoroethylene)(PVDF-TrFE)and polyamide 11(nylon-11).And these materials were subsequently investigated.Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)was added to PVDF-TrFE to enhance the ferroelectric crystalline phase.X-ray diffraction analysis revealed that this incorporation affects theβphase.In addition,the surface of nylon-11 was modified using the electrospray technique for post-treatment,thereby improving the interfacial adhesion between the fibers.These materials were then utilized in fibrous-mat ATENGs(FM-ATENGs)to demonstrate their practical application.The FM-ATENGs can be effectively used in an Arduino airflowcheck sensor,showcasing their potential for application in HVAC systems,to enhance airflow control and energy efficiency.

Pyrolysis behaviour and kinetic analysis of waste polylactic acid composite reinforced with reed straw processing residue

The lignocellulose reinforced composites are commonly used sustainable materials with good mechanical and physical properties.Aiming to properly dispose and recover the potential value of discarded lignocellulose reinforced composites,the pyrolysis behaviour and kinetics of reed straw processing residual/polylactic acid(RSPR/PLA)composites,a typical 3D printing material,was investigated.Based on the TG-FTIR results,the synergistic effects between RSPR and PLA during the pyrolysis process were clarified.Compared with the FTIR spectra of PLA,the absorption peaks of CO and CO_(2)disappear in the FTIR spectra of RSPR/PLA composite,which indicates RSPR provides additional free radicals for the free radical reaction of PLA,and further promoting the decomposition.The apparent activation energy of the RSPR/PLA composite pyrolysis was calculated by two iso-conversional methods including Flynn-Wall-Ozawa(FWO)and Kissinger-Akahira-Sunose(KAS).The average Ea of the RSPR/PLA composite(122.6 kJ mol^(-1)(FWO)and 117.9 kJ mol^(-1)(KAS))was lower than that of solo pyrolysis of RSPR(138.5 kJ mol^(-1)(FWO)and 135.4 kJ mol^(-1)(KAS))and the pure PLA(197.0 kJ mol^(-1)(FWO)and 196.6 kJ mol^(-1)(KAS)).The master plot method results suggested the pyrolysis of RSPR/PLA composite followed the one-dimensional(D1)diffusion model.This work provides an environmentally friendly strategy to effective thermo-chemical upgrading of the value of discarded lignocellulose reinforced composite material.

Selectivity of CO_(2)reduction reaction to CO on the graphitic edge active sites of Fe-single-atom and dual-atom catalysts:A combined DFT and microkinetic modeling

We study the carbon dioxide reduction reaction(CO_(2)RR)activity and selectivity of Fe single-atom catalyst(Fe-SAC)and Fe dual-atom catalyst(Fe-DAC)active sites at the interior of graphene and the edges of graphitic nanopore by using a combination of DFT calculations and microkinetic simulations.The trend of limiting potentials for CO_(2)RR to produce CO can be described by using either the adsorption energy of COOH,CO,or their combination.CO_(2)RR process with reasonable reaction rates can be achieved only on the active site configurations with weak tendencies toward CO poisoning.The efficiency of CO_(2)RR on a catalyst depends on its ability to suppress the parasitic hydrogen evolution reaction(HER),which is directly related to the behavior of H adsorption on the catalyst’s active site.We find that the edges of the graphitic nanopore can act as potential adsorption sites for an H atom,and in some cases,the edge site can bind the H atom much stronger than the main Fe site.The linear scaling between CO and H adsorptions is broken if this condition is met.This condition also allows some edge active site configurations to have their CO_(2)RR limiting potential lower than the HER process favoring CO production over H2 production.

Prognostics and health management of alkaline water electrolyzer: Techno-economic analysis considering replacement moment

Recently,considerable attention has been paid to the installation of renewable energy capacity to mitigate global CO_(2) emissions.H_(2) produced using water electrolysis and renewable energy is regarded as a clean energy carrier,generating electricity without CO_(2) emissions,called‘Green H 2’.In this paper,a prognostics and health man-agement model for an alkaline water electrolyzer was proposed to predict the load voltage on the electrolyzer to obtain the state of health information.The prognostics and health management model was developed by training historical operating data via machine learning models,support vector machine and gaussian process regression,showing the root mean square error of 1.28×10^(−3) and 8.03×10^(−6).In addition,a techno-economic analysis was performed for a green H_(2) production system,composed of 1 MW of photovoltaic plant and 1 MW of alkaline water electrolyzer,to provide economic insights and feasibility of the system.A levelized cost of H_(2) of$6.89 kgH_(2)−1 was calculated and the potential to reach the levelized cost of H_(2) from steam methane reforming with carbon capture and storage was shown by considering the learning rate of the photovoltaic module and elec-trolyzer.Finally,the replacement of the alkaline water electrolyzer at around 10 years was preferred to increase the net present value from the green H_(2) production system when capital expenditure and replacement cost are low enough.

Efficient gasification of wet biomass residue to produce middle caloric gas

Various process residues represent a kind of biomass resource already concentrated but containing water as much as 60 wt.%. These materials are generally treated as waste or simply combusted directly to generate heat. Recently, we attempted to convert them into middle caloric gas to substitute for natural gas, as a chemical or a high-rank gaseous fuel for advanced combustion utilities. Such conversion is implemented through dual fluidized bed gasification （DFBG）. Concerning the high water content of the fuels, DFBG was suggested to accomplish either with high-efficiency fuel drying in advance or direct decoupling of fuel drying/pyrolysis from char gasification and tar/hydrocarbon reforming. Along with fuel drying, calcium-based catalyst can be impregnated into the fuel, without much additional cost, to increase the fuel＇s gasification reactivity and to reduce tar formation. This article reports the Ca impregnation method and its resulting effects on gasification reactivity and tar suppression ability. Meanwhile, the principle of directly gasifying wet fuel with decoupled dual fluidized bed gasification （D-DFBG） is also highlighted.

End-of-life batteries management and material flow analysis in South Korea

Consumers increasingly have worn-out batteries as electrical and electronic equipment with new technical developments are introduced into the market and quickly replace older models. As a result, large amounts of end-of-life （EOL） or waste batteries are generated. Such batteries may contain a variety of materials that includes valuable resources as well as toxic elements. Thus, the proper recycling and management of batteries is very important from the perspective of resource conservation and environmental effect. The collection and recycling of EOL batteries is relatively low in South Korea compared to other countries, although an extended producer responsibility （EPR） policy was adopted for battery recycling in 2003. In this study, the management and material flow of EOL batteries is presented to determine potential problems and quantitative flow, based on literature review, site visits to battery recycling facilities, and interviews with experts in the Korea Battery Recycling Association （KBRA）, manufacturers, and regulators in government. The results show that approximately 558 tons of manganese-alkaline batteries, the largest fraction among recycling target items, was disposed in landfills or incinerators in 2015, while approximately 2,000 tons of batteries were recovered at a recycling facility by simple sorting and crushing processes. By raising environmental awareness, more diverse and effective collection systems could be established for consumers to easily dispose of EOL batteries in many places. Producers, retailers and distributors in South Korea should also play an important role in the collection of EOL batteries from consumers. Lithium-ion batteries from many electronic devices must be included in the EPR system for resource recovery.

Active Noise Control for Vehicle Exhaust Noise Reduction

An active noise control (ANC) method was developed for exhaust noise reduction for medium-duty diesel trucks. A modified variable step size least mean squares (LMS) algorithm was used for the controller in a variable environment that considered the vehicle's acceleration characteristics. The variable step size time-based synchronized filtered-x LMS method (SFX-TB) used an adaptive algorithm that was more efficient than the conventional filtered-x LMS algorithm. The simulation and the experimental tests show that the control trackability and stability provided by the algorithm during acceleration enable the ANC system to effectively reduce the vehicle exhaust noise.