三维有序大孔钙钛矿材料在环境领域的应用（英文）

近年来,三维有序大孔(3DOM)材料吸引了世界各国研究者的广泛关注.除了表面积大、孔隙率高、孔体积大、传质性能好等大孔材料的普遍特性,3DOM材料的孔结构分布均匀,且具有规律的周期性,其大孔尺寸也可在制备过程中自由调控.在制备过程中,通过加入适当的表面活性剂,可以得到骨架上具有介孔的3DOM材料.这使3DOM材料具有了多级孔结构,为其提供了更多的反应活性位点和对反应物的尺寸选择性.此外,作为一种三维光子晶体,3DOM材料还具有光子禁带、慢光效应等独特的光学性质.钙钛矿是一类广泛分布于地球上且储量丰富的化合物,具有成本低廉、氧化还原性能好、离子迁移率高、稳定性高、毒性较低、生物相容性好等优点.并且通过部分或完全取代钙钛矿材料中位于A位或B位的阳离子,可以有效调控其物理化学性质,使其在环境领域中表现出巨大的应用潜力.3DOM钙钛矿材料结合了3DOM结构和钙钛矿材料各自的优点,逐渐成为了环境领域中的热门材料.已被广泛应用于光催化分解水产氢或降解污染物、碳烟催化燃烧、挥发性有机化合物(VOCs)催化氧化、温室气体减排和利用、传感器等多种环境应用领域.本文综述了近年来3DOM钙钛矿材料的一般合成方法,并列举了3DOM钙钛矿材料在环境领域的应用和研究进展,详细讨论了其在不同反应体系中的独特优势和反应机理.除了3DOM钙钛矿材料灵活的组成及可调变的物理化学性质对于其催化性能的提升具有显著的作用.此外,在光催化中,3DOM材料独特的慢光效应,使半导体材料的光吸收范围与光子禁带边重叠时,可以显著提高半导体材料的光吸收效率,进而有效提高催化剂的光催化活性.因此,3DOM材料的结构有序性和光子禁带调控是3DOM钙钛矿材料在光催化领域应用中的关键因素.对于碳烟催化燃烧,由于碳烟颗粒尺寸较大,碳烟颗粒与催化活性位点的接触成为影响催化活性的关键因素.因此,3DOM钙钛矿材料的大孔孔径,特别是其孔与孔之间的窗口尺寸对于其催化性能起着重要的作用.而对于VOCs催化氧化、CH4催化燃烧、CO2甲烷化、传感器等应用领域,3DOM钙钛矿材料比表面积的提升以及多级孔道结构的构建对催化活性的促进作用更为显著.最后,本文提出了该研究领域所面临的挑战,并对未来的发展进行了展望.

Development and Application of Meteorological Disaster Monitoring and Early Warning Platform for Characteristic Agriculture in Huzhou City Based on GIS

Based on the needs of characteristic agricultural production for meteorological services in Huzhou City,we use C# programming language to develop the meteorological disaster monitoring and early warning platform for characteristic agriculture in Huzhou City. This platform integrates the functions of meteorological and agricultural information monitoring,disaster identification and early warning,fine weather forecast product display,and data query and management,which effectively enhances the capacity of meteorological disaster monitoring and early warning for characteristic agriculture in Huzhou City,and provides strong technical support for the meteorological and agricultural departments in the agricultural meteorological services.

Current status and prospects of terminal guidance laws for intercepting hypersonic vehicles in near space:a review

The unique performance advantages of hypersonic vehicles represent a critical challenge for existing defense systems.To facilitate defensive operations against hypersonic vehicles in near space,this paper systematically discusses both the advantages of these vehicles and the difficulties in intercepting them.Focusing on the state-of-the-art terminal guidance laws for intercepting hypersonic vehicles in near space,we examine research progress in the area of single-and multi-interceptor cooperative guidance laws and summarize their advantages and disadvantages.We also highlight future research directions for developing an effective terminal guidance law for multi-interceptor cooperative interception of hypersonic vehicles,based on four aspects:the information domain,space domain,physical domain,and effect-cost ratio.The findings provide a reference for further research into near-space interceptor terminal guidance technologies.

ZnFe_(2)O_(4)/BiVO_(4)Z-scheme heterojunction for efficient visible-light photocatalytic degradation of ciprofloxacin

A novel Z-scheme ZnFe_(2)O_(4)/BiVO_(4)heterojunction photocatalyst was successfully synthesized using a convenient solvothermal method and applied in the visible light photocatalytic degradation of ciprofloxacin,which is a typical antibiotic contaminant in wastewater.The heterostructure of as-synthesized catalysts was confirmed using X-ray diffraction,scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations.Compared with the singlephase counterparts,ZnFe_(2)O_(4)/BiVO_(4)demonstrated considerably enhanced photogenerated charge separation efficiencies because of the Z-scheme transfer mechanism of electrons between the composite photocatalysts.Consequently,the 30%ZnFe_(2)O_(4)/BiVO_(4)catalyst afforded a degradation rate of up to 97%of 20 mg/L ciprofloxacin under 30 min of visible light irradiation with a total organic carbon removal rate of 50%,which is an excellent activity compared with ever reported BiVO_(4)-based catalysts.In addition,the liquid chromatography-mass spectrometry and quantitative structure-activity relationships model analyses demonstrated that the toxicity of the intermediates was lower than that of the parent ciprofloxacin.Moreover,the as-synthesized ZnFe_(2)O_(4)/BiVO_(4)heterojunctions were quite stable and could be reused at least four times.This study thus provides a promising Z-scheme heterojunction photocatalyst for the efficient removal and detoxication of antibiotic pollutants from wastewater.

Application of activated carbon derived from scrap tires for adsorption of Rhodamine B

Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char （APTC） for Rhodamine B （RhB）. Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.

Preparation of Fe_x Ce_(1-x) O_y solid solution and its application in Pd-only three-way catalysts

FeOx-CeO2 mixed oxides with increasing Fe/（Ce＋Fe） atomic ratio （1-20 mol%） were prepared by sol-gel method and characterized by X-ray powder diffraction （XRD）, Brunauer-Emrnett-Teller （BET） and Hydrogen temperature-programmed reduction （H2-TPR） techniques. The dynamic oxygen storage capacity （DOSC） was investigated by mass spectrometry with CO/O2 transient pulses. The powder XRD data following Rietveld refinement revealed that the solubility limit of iron oxides in the CeO2 was 5 mol% based on Fe/（Ce＋Fe）. The lattice parameters experienced a decrease followed by an increase due to the influence of the maximum solubility limit of iron oxides in the CeO2. TPR analysis revealed that Fe introduction into ceria strongly modified the textual and structural properties, which influenced the oxygen handling properties. DOSC results revealed that Ce-based materials containing Fe oxides with multiple valences contribute to the majority of DOSC. The kinetic analysis indicated that the calculated apparent kinetic parameters obey the compensation effect. The three-way catalytic performance for Pd-only catalysts based on the Fe doping support exhibited the redundant iron species separated out of the CeO2 and interacted with the ceria and Pd species on the surface, which seriously influenced the catalytic properties, especially after hydrothermal aging treatment.

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl-2-furfural

A base-free catalytic system for the aerobic oxidation of 5-hydroxymethyl-2-furfural was exploited by using Pt nanoparticles immobilized onto a thermoresponsive poly(acrylamide-co-acrylonitrile)-b-poly(N-vinylimidazole)block copolymer,with an upper critical solution temperature of about 45°C.The Pt nanocatalysts were well-dispersed and highly active for the base-free oxidation of 5-hydroxymethyl-2-furfural by molecular oxygen in water,affording high yields of 2,5-furandicarboxylic acid(up to>99.9%).The imidazole groups in the block copolymer were conducive to the improvement of catalytic performance.Moreover,the catalysts could be easily separated and recovered based on their thermosensitivity by cooling the reaction system below the upper critical solution temperature.Good stability and reusability were observed over these copolymer-immobilized catalysts with no obvious decrease in catalytic activity in the five consecutive cycles.

Superior performance in visible-light-driven hydrogen evolution reaction of three-dimensionally ordered macroporous SrTiO_(3) decorated with Zn_(x)Cd_(1−x)S

It is of broad interest to develop emerging photocatalysts with excellent light-harvesting capacity and high charge carrier separation efficiency for visible light photocatalytic hydrogen evolution reaction.However,achieving satisfying hydrogen evolution efficiency under noble metal-free conditions remains challenging.In this study,we demonstrate the fabrication of three-dimensionally ordered macroporous SrTiO_(3)decorated with Zn_(x)Cd_(1−x)S nanoparticles for hydrogen production under visible light irradiation(λ>420 nm).Synergetic enhancement of photocatalytic activity is achieved by the slow photon effect and improved separation efficiency of photogenerated charge carriers.The obtained composites could afford very high hydrogen production efficiencies up to 19.67 mmol·g^(−1)·h^(−1),with an apparent quantum efficiency of 35.9%at 420 nm,which is 4.2 and 23.9 times higher than those of pure Zn_(0.5)Cd_(0.5)S(4.67 mmol·g^(−1)·h^(−1))and CdS(0.82 mmol·g^(−1)·h^(−1)),respectively.In particular,under Pt-free conditions,an attractive hydrogen production rate(3.23 mmol·g^(−1)·h^(−1))was achieved,providing a low-cost and high-efficiency strategy to produce hydrogen from water splitting.Moreover,the composites showed excellent stability,and no obvious loss in activity was observed after five cycling tests.

Spontaneous migration induced Co nanokarstcave encapsulated in N-doped carbon hybrids for efficient oxygen electrocatalyst

Despite the extensive application of porous nanostructures as oxygen electrocatalysts, it is challenging to synthesize single-metal state materials with porous structures, especially the ultrasmall ones due to the uniform diffusion of the same metal. Herein, we pioneer demonstrate a new size effect-based controllable synthesis strategy for the homogeneous Co nanokarstcaves assisted by Co-CN hybrids (CCHs). The preferential migration of cobalt atoms on the surface of small size zeolitic imidazolate framework (ZIF) with high surface energy during pyrolysis is the key factor for the formation of nanokarstcave structure. Furthermore, graphene can act as a diffusion barrier to prevent the agglomeration of nanoparticles in the synthesis process, which also plays an important role in the formation of porous nanostructures. In alkali media, CCHs achieve overpotential of 287 mV (@10 mA·cm^(−2)) for oxygen evolution reaction (OER) and a half wave potential of 0.86 V (vs. RHE) for oxygen reduction reaction (ORR).

Fertilizer sphericity measuring device based on equatorial and meridian circles

Fertilizer sphericity is an important assessment index of appearance quality that affects the fertilization effect.A fertilizer sphericity measuring device based on machine vision was designed aimed at low precision and heavy workload of manual fertilizer measurement,and high cost and complicated operation of high precision measuring instruments.A fertilizer sphericity measuring method based on equatorial and meridian circles was proposed.The device works in an intermittent static acquisition mode to simultaneously obtain both top and side images of a single fertilizer.First,the method performs gamma correction on the top and side images of the single fertilizer,and uses the Canny operator to detect the edge of the image to obtain the equatorial and meridian circular contour images of the fertilizer.Second,based on the fertilizer equatorial and meridian circular contour,the Least Squares Circle method was used to evaluate the roundness of the single fertilizer.Finally,the average roundness value of the equatorial and meridian circles was used as the final sphericity value of the fertilizer.The sphericity measurement test was carried out on the same batch of compound,organic and biological fertilizers by using the sphericity measuring device.The fertilizer sphericity data were obtained by different measurement and evaluation methods.The variation coefficient was used to evaluate the difference in fertilizer sphericity measured by different sphericity measurement and evaluation methods.The results show that among the different measurement and evaluation methods,the coefficient of variation of fertilizer sphericity measured by the equatorial and meridian circle method was the smallest,and the coefficient of variation of sphericity measured by the Least Squares Circle method was the smallest and accurate.This study shows that the sphericity measuring device and method can accurately measure the fertilizer sphericity,and has a significant potential to facilitate fertilizer production and quality inspection.