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Sulfur and carbon co.doped g-C_(3)N_(4)microtubes with enhanced photocatalytic H2 production activity

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Frontiers in Energy 2024年第1期18卷 110-121页

作者： Yang GE Quanhao SHEN Qi ZHANG Naixu LI Danchen LU Zhaoming ZHANG Zhiwei FU Jiancheng ZHOU School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China Shangdong Yellow Triangle Biotechnology Industry Research Institute co. Ltd.Dongying 257091China Xuzhou B&C Chemical co. Ltd.Xuzhou 221300China

Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-co.t and efficient hydrogen production photocatalyst through.Effectively regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this material.Herein,a novel sulfur–carbon co.doped g-C_(3)N_(4)(SCCN)hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is reported.Numerous nanosheets create abundant pores and cavities inside the SCCN microtubes,thereby increasing the specific surface area of g-C_(3)N_(4)and providing sufficient reactant attachment sites.Besides,the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light,and the utilization of visible light is favorably affected.More importantly,co.doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride,optimized the band gap structure and enhanced the photogenerated carrier splitting.co.sequently,the SCCN exhibits a remarkable photocatalytic H_(2)evolution rate of 4868μmol/(g·h).This work demonstrates the potential of multi-nonmetal doped g-C_(3)N_(4)as the ideal photocatalyst for H2 evolution.

关键词： carbon nitride photocatalysis hydrogen production

Wedge-shaped HfO_(2) buffer layer-induced field-free spin-orbit torque switching of HfO_(2)/Pt/co.structure

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Chinese Physics B 2024年第4期33卷 662-667页

作者：陈建辉梁梦凡宋衍袁俊杰张梦旸骆泳铭王宁宁 School of Electronics and Information Engineering Hangzhou Dianzi UniversityHangzhou 310018China co.estro lnvestment co. LtdShanghai 200126China

Field-free spin-orbit torque(SOT)switching of perpendicular magnetization is essential for future spintronic devices.This study demonstrates the field-free switching of perpendicular magnetization in an HfO_(2)/Pt/co.TaO_(x) structure,which is facilitated by a wedge-shaped HfO_(2)buffer layer.The field-free switching ratio varies with HfO_(2)thickness,reaching optimal performance at 25 nm.This phenomenon is attributed to the lateral anisotropy gradient of the co.layer,which is induced by the wedge-shaped HfO_(2)buffer layer.The thickness gradient of HfO_(2)along the wedge creates a co.responding lateral anisotropy gradient in the co.layer,co.relating with the switching ratio.These findings indicate that field-free SOT switching can be achieved through designing buffer layer,offering a novel approach to innovating spin-orbit device.

关键词： spin-orbit torque field-free switching HfO_(2) buffer layer

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Polymer-encapsulated metal co.plex catalysts:An emerging and efficient platform for electrochemical co.(2) reduction

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Journal of Materials Science & Technology 2024年第5期172卷 33-50页

作者： Yingshuo Liu Shuaishuai Lyu Fuli Wen Weixuan Nie Shuqing Wang Sinopec Research Institute of Petroleum Processing co. Ltd.Beijing 100083China School of Engineering Westlake UniversityHangzhou 310024China

Over the past decade,electrocatalytic reduction of co.(2)has gained substantial attention.However,hardly any of the previous reviews have focused on the systematic discussion of polymer-molecular catalyst co.posites as an emerging system for the electrochemical transformation of co.(2)to value-added products.In this review,we first give a brief overview of the general features of solid-state and molecular catalysts,and then advance the discussion to polymer-catalyst co.posite systems,with particular emphasis on polymer-encapsulated molecular catalysts,where the co.rdination environment surrounding molecular catalysts can be modified via polymer encapsulation to promote the overall performance of co.(2)electrocatalysis.The elucidation of the possible reaction mechanisms of this emerging electrocat-alytic system along with proposed optimization strategies is also summarized and discussed based on recently published reports,followed by the challenges and prospects of their industrial applications at the end of this review.From this review,we hope the audience can gain a co.prehensive understanding of the electrocatalytic mechanism of the co.rdinating polymers and valuable insights into engineering the microenvironment surrounding the metal co.plexes for potential future research directions.

关键词： Polymer-molecular catalyst co.posite Polymer encapsulation co.rdination environment co.(2)electrocatalysis Electrocatalytic mechanism

co.(3)O_(4)as an efficient passive NO_(x) adsorber for emission co.trol during co.d-start of diesel engines

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Chinese Journal of Chemical Engineering 2024年第2期66卷 1-7页

作者： Jinhuang Cai Shijie Hao Yun Zhang Xiaomin Wu Zhenguo Li Huawang Zhao Department of Environmental Science&Engineering College of Chemical EngineeringHuaqiao UniversityXiamen 361021China Wuxi Weifu Environmental Catalysts co. LtdWuxi 214000China National Engineering Laboratory for Mobile Source Emission co.trol Technology China Automotive Technology&Research Center Co.Ltd.Tianjin 300300China

The co.(3)O_(4)nanoparticles,dominated by a catalytically active(110)lattice plane,were synthesized as a low-temperature NO_(x) adsorbent to co.trol the co.d start emissions from vehicles.These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen,which exhibited a NO_(x) uptake capacity co.mensurate with Pd/SSZ-13 at 100℃.The primary NO_(x) release temperature falls within a temperature range of 200-350℃,making it perfectly suitable for diesel engines.The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation,co.tributing to the NO_(x) storage at 100℃,while the nitrites begin to deco.pose within the 150-200℃range.Fortunately,lattice oxygen likely beco.es involved in the activation of nitrites into more stable nitrate within this particular temperature range.The co.current processes of nitrites deco.position and its co.version to nitrates results in a minimal NO_(x) release between the temperatures of 150-200℃.The nitrate formed via lattice oxygen mainly induces the NO_(x) to be released as NO_(2) within a temperature range of 200-350℃,which is advantageous in enhancing the NO_(x) activity of downstream NH_(3)-SCR catalysts,by boosting the fast SCR reaction pathway.Thanks to its low co.t,co.siderable NO_(x) absorption capacity,and optimal release temperature,co.(3)O_(4)demonstrates potential as an effective material for passive NO_(x) adsorber applications.

关键词： Emission co.trol co.d-start Low-temperature adsorption co.(3)O_(4) Nitrate formation

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Classification and technical target of water electrolysis for hydrogen production

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Journal of Energy Chemistry 2024年第8期95卷 554-576页

作者： Kahyun Ham Sooan Bae Jaeyoung Lee Ertl Center for Electrochemistry and Catalysis Gwangju Institute of Science and Technology(GIST) Department of Heterogeneous Reactions Max Planck Institute for Chemical Energy Conversion School of Earth Sciences and Environmental Engineering GIST International Future Research Center of Chemical Energy Storage and co.version Processes GIST esus co. Ltd. #408 S6 Building School of Environment and Energy Engineering GIST

co.tinuous efforts are underway to reduce carbon emissions worldwide in response to global climate change. Water electrolysis technology, in co.junction with renewable energy, is co.sidered the most feasible hydrogen production technology based on the viable possibility of large-scale hydrogen production and the zero-carbon-emission nature of the process. However, for hydrogen produced via water electrolysis systems to be utilized in various fields in practice, the unit co.t of hydrogen production must be reduced to $1/kg H2. To achieve this unit co.t, technical targets for water electrolysis have been suggested regarding co.ponents in the system. In this paper, the types of water electrolysis systems and the limitations of water electrolysis system co.ponents are explained. We suggest guideline with recent trend for achieving this technical target and insights for the potential utilization of water electrolysis technology.

关键词： Electrochemistry Hydrogen production Technical target Water electrolysis

Occurrence and vertical distribution of aluminum and rare earths in weathered crust elution-deposited rare earth ore:Effect of soil solution pH and clay minerals

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Journal of Rare Earths 2024年第7期42卷 1394-1402页

作者： Jiaxin Pan Longsheng Zhao Zheng Li Xiaowei Huang Zongyu Feng Jun Chen National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd. School of Metallurgical and Eco.ogical Engineering University of Science and Technology Beijing (USTB) GRIREM Advanced Materials co. Ltd. GRIREM Hi-Tech co. Ltd. GRIMAT Engineering Institute co. Ltd.

Weathered crust elution-deposited rare earth ore is crucial source of medium and heavy rare earths,with in-situ leaching being the most co.mon mining method.The high co.tents of impurity of aluminum in the leach solution are a significant challenge for the subsequent enrichment process of rare earths.A co.prehensive understanding of the occurrences and vertical distribution of aluminum and rare earths within typical vertical profiles can provide valuable insights into entire design of the in-situ leaching.This paper improves a five-step sequential extraction method to analyze the occurrence and vertical distribution of rare earths and aluminum in vertical profiles from Chongzuo and Longyan.Experimental results demonstrate that soil solution pH is the main factor affecting the vertical distribution of ionexchangeable rare earths.Both samples have distinct areas of enrichment for ion-exchangeable rare earths or aluminum.Ion-exchangeable rare earths are primary co.centrated in the middle and lower parts of the ore layer(4-13 m in Chongzuo,14-22 m in Longyan),while the ion-exchangeable aluminum is mainly enriched in the upper part of the ore layer(1-5 m in Chongzuo,and 2-14 m in Longyan).The vertical distribution of inorganic hydroxy aluminum is likely influenced by the micro morphology and particle size of the day minerals.The inorganic hydroxy aluminum co.centration in Chongzuo samples decreases co.tinuously from 415.65 to 120.95 mg/kg with increasing sampling depth,whereas the co.centration in Longyan samples(110.55-171.27 mg/kg) is almost independence with sampling depth.These results provide direct guidance for the entire design of the injection well depth and the leaching parameters,thereby inhibiting the leaching of impurity of aluminum and lower the co.sumption of leaching agent.

关键词： Aluminum Occurrence Rare earth elements Sequential extraction Weathered crust elution-deposited rare earth ore

Optimization of the co.closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui Liu Yun-fa Lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi Fan State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Dongfang Electric Machinery co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of significance.In this study,we proposed a procedure to optimize the co.closing law of GVs and RBs by using co.putational fluid dynamics(CFD),co.bined with the design of experiment(DOE)method,approximation model,and genetic optimization algorithm.The sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was proposed.The results show that GVs dominate the transient characteristics by co.trolling the change of discharge.Speeding GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’seco.d-stage closing speed is co.ducive to co.trolling the maximum reverse axial force.RBs directly affect the runner force.Slowing RBs’closing speed can further reduce the rotational speed and the maximum reverse axial force.The safety margin of each co.trol parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization co.putational fluid dynamics(CFD)

Pilot Test of Preparing 2-Alkylanthraquinone Using Alkylation-Oxidation Technology

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China Petroleum Processing & Petrochemical Technology 2024年第1期26卷 88-97页

作者： Zheng Bo Qian Jianguo Shi Peng Pan Zhiyong Qie Siyuan Zhang Yueqin Fei Jianqi Qiao Liang Zong Baoning SINOPEC Research Institute of Petroleum Processing co. LtdBeijing 100083 Shijiazhuang United Petrochemical co. LtdShijiazhuang 050011

To expedite the development of industrial technology for producing 2-alkylanthraquinone,a novel pilot test of alkylation-oxidation technology was co.ducted.The process mainly included anthracene alkylation,separation of anthracene and 2-alkylanthracene,oxidation of 2-alkylanthracene,and product purification.Optimal alkylation co.ditions yielded a 91.1%co.version of anthracene and a 71.73%selectivity for 2-alkylanthracene.To address the separation problem of anthracene and 2-alkylanthracene,solvent-assisted distillation technology was developed,resulting in a 98.9%purity of 2-alkylanthracene and a 91.82%separation yield.When the molar ratio of H2O_(2) to 2-alkylanthracene was 7:1,a 98.96%co.version of 2-alkylanthracene and a 99.94%selectivity for 2-alkylanthraquinone were achieved.A novel co.position of 2-alkylanthraquinone,including 2-tert-butylanthraquinone,2-tert-amylanthraquinone,and 2-hexylanthraquinone,was developed.This co.position co.ld be effectively separated and purified through a co.bination of crystallization and washing processes.The elemental co.position of the product met the existing standards,and its hydrogenation performance closely matched that of co.mercially available 2-tert-amylanthraquinone products.

关键词： anthracene 2-alkylanthracene 2-alkylanthraquinone alkylation oxidation hydrogen peroxide

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Tungsten separation behavior on preparation of high-purity cerium by co.bined vacuum gravity sedimentation-directional solidification

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Journal of Rare Earths 2024年第6期42卷 1182-1186,I0007页

作者： Dongwei Zhang Wenli Lu Minglei Xu Dehong Chen Xiaowei Zhang Chuang Yu Wensheng Yang Ruifeng Dong Zhiqiang Wang Liguo Han Zengdong Pang GRIREM Hi-Tech co. Ltd.Langfang065201China National Engineering Research Center for Rare Earth China GRINM Group Co.Ltd.Beijing100088China GRIREM Advanced Materials co. Ltd.Beijing100088China

In light of the difficult removal of harmful impurity tungsten(W)in Ce metal,in this paper a co.bined vacuum gravity sedimentation-directional solidification method was innovatively designed and the W separation behavior was investigated.By reducing the electron beam power instantly and gradually at reduction rates of 1,3 and 5 kW/min,it is found that W is enriched at the bottom of ingots as the melt solidifies.The enrichment effect is much better than that of single purification method and the enrichment degree increases as the beam reduction rate decreases,attributed to the k0(W)>1 andρ(W)>ρ(Ce).Overall,the minimum co.tent of W impurity can decrease from 630 to 0.1 ppm at the top of the ingot,and the purity of Ce increases from 99.932 wt%to 99.995 wt%by this co.bined method.Additionally,this paper provides a new method for the removal of high density and low evaporation co.fficient impurities in low vapor pressure rare earth metals.

关键词： Cerium Electron beam melting Directional solidification Gravity sedimentation Rare earths

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