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Application of surfactant for improving leaching process of weathered crust elution-deposited rare earth ores

Journal of Rare Earths 2024年第1期42卷 181-190,I0007页

作者： Fang Zhou Lisen Zhang Zhiwei Wang Yixin Zhang Ru'an Chi Xiaoyan Wu key laboratory for green chemical Process of ministry of education Wuhan Institute of TechnologyWuhan430073China

Weathered crust elution-deposited rare earth ores(WREOs)in China are the main source of medium and heavy rare earths in the world.In order to improve the seepage and the mass transfer of traditional ammonium salt leaching process of WREOs,surfactants were added in the ammonium sulfate leaching solution and the ammonium chloride leaching solution.The leaching kinetics,the mass transfer process,and the adhesion work reduction factor calculated from the interfacial properties were studied to reveal the strengthening mechanism of surfactant.In the presence of the tested five surfactants,cetyl trimethyl ammonium bromide(CTAB),dodecyl trimethyl ammonium bromide(DTAB),sodium dodecyl sulfate(SDS),sodium oleate and oleic acid,the permeability of WREOs is improved,the rare earth(RE)leaching efficiency increase and the impurity aluminum(Al)leaching efficiency decrease,indicating its promotional effect on the leaching process of WREOs.Furthermore,CTAB shows a better leaching enhancement,and the optimal addition dosage is 0.4 g/L for the two ammonium salt leaching agent systems.The kinetics analysis shows the internal diffusion controls model of RE and Al leaching process,and the leaching kinetics equations of RE and Al related to CTAB concentration were obtained for the two ammonium salt leaching systems.According to the chromatographic plate theory,the mass transfer efficiency of RE increases with the CTAB concentration increasing until 0.4 g/L,which confirms that the optimal CTAB addition is 0.4 g/L.Smaller adhesion work and adhesion work reduction factor indicate more favorable permeation as well as the leaching process.

关键词： Weathered crust elution-deposited rare earth ores Surfactant Kinetics Mass transfer

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Combined effects of sea urchin-like structure and mixed Cu^(+)/Cu^(0)states on promoting C_(2)formation in electrocatalytic CO_(2)reduction

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Frontiers of chemical Science and Engineering 2024年第3期18卷 63-73页

作者： Mengqing Shan Dongsheng Lu Jiatong Dong Shen Yan Jinyu Han Hua Wang Collaborative Innovation Center of chemical Science and Engineering Key Laboratory for Green Chemical Technology of the Ministry of EducationSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin300354China

Surface engineering and Cu valence regulation are essential factors in improving the C_(2)selectivity during the electrochemical reduction of CO_(2).Herein,we present a sea urchin-like CuO/Cu_(2)O catalyst derived from rhombic dodecahedra Cu_(2)O through one-step oxidation/etching method where the mixed Cu^(+)/Cu^(0)states are formed via in situ reduction during electrocatalysis.The combined effects of the morphology and the mixed Cu^(+)/Cu^(0)states on C–C coupling are evaluated by the Faradaic efficiency of C_(2)and the C_(2)/C1 ratio obtained in an H-cell.R-Cu^(O)/Cu_(2)O exhibited 49.5%Faradaic efficiency of C_(2)with a C_(2)/C1 ratio of 3.1 at−1.4 V vs.reversible hydrogen electrode,which are 1.5 and 3.2 times higher than those of R-Cu_(2)O,respectively.Using a flow-cell,68.0%Faradaic efficiency of C_(2)is achieved at a current density of 500 mA·cm^(−2).The formation of the mixed Cu^(+)/Cu^(0)states was confirmed by in situ Raman spectra.Additionally,the sea urchin-like structure provides more active sites and enables faster electron transfer.As a result,the excellent C_(2)production on R-CuO/Cu_(2)O is primarily attributed to the synergistic effects of the sea urchin-like structure and the stable mixed Cu^(+)/Cu^(0)states.Therefore,this work presents an integrated strategy for developing Cu-based electrocatalysts for C_(2)production through electrochemical CO_(2)reduction.

关键词： CO_(2)electrolysis sea urchin-like structure Cu^(+)/Cu^(0) C_(2)products

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Insight into the adsorption behavior and mechanism of trace impurities from H_(2)O_(2)solution on functionalized zirconia by tuning the structure of amino groups

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Frontiers of chemical Science and Engineering 2024年第5期18卷 83-94页

作者： Yu Meng Yitong Wang Guozhu Li Guozhu Liu Li Wang key laboratory for green chemical technology of ministry education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Haihe laboratory of Sustainable chemical Transformations Tianjin 300192China

Primary,secondary and tertiary amino-functionalized zirconia(ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N)was synthesized by the postgrafting method for the adsorption removal of typical metallic ions,phosphate and total oxidizable carbon from a real H_(2)O_(2)solution.ZrO_(2)-NH_(2),ZrO_(2)-NH and ZrO_(2)-N exhibited similar pore sizes and sequentially increased zeta potentials.The adsorption results of single and binary simulated solutions showed that the removal efficiency increased in the order of Fe^(3+)>Al^(3+)>Ca^(2+)>Na^(+).There is competitive adsorption between metallic ions,and Fe^(3+)has an advantage over the other metals,with a removal efficiency of 90.7%.The coexisting phosphate could promote the adsorption of metallic ions,while total oxidizable carbon had no effect on adsorption.The adsorption results of the real H_(2)O_(2)solution showed that ZrO_(2)-NH_(2)exhibited the best adsorption affinity for metallic ions,as did phosphate and total oxidizable carbon,with a total adsorption capacity of 120.9 mg·g_(-1).Density functional theory calculations revealed that the adsorption process of metallic ions involves electron transfer from N atoms to metals and the formation of N-metal bonds.

关键词： adsorption metallic ion phosphate total oxidizable carbon zirconia H_(2)O_(2)

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Multiple exciton generation effect in photocatalytic overall water splitting

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Science China Chemistry 2024年第2期67卷 424-425页

作者： Xiaolei Guo Ji-Jun Zou key laboratory for green chemical technology of ministry of education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China

This highlight is based on recent research published in Nature Energy by Li and co-workers [1] from Northwestern Polytechnology University, reporting an exceeding 100% internal quantum efficiency(IQE) in photocatalytic overall water splitting. This breakthrough promises a bright future for efficient photocatalyst design by utilizing the multiple exciton effect(MEG).

关键词： splitting effect utilizing

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NaBH4-induced phase transition of CoSe_(2) with abundant Se deficiency for acidic oxygen reduction to hydrogen peroxide

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Rare Metals 2024年第2期43卷 500-510页

作者： Cai-Di Han Yong-Chao Zhang Qian Zhang Jin-Ting Wu Jian Gao Ji-Jun Zou Xiao-Dong Zhu State key laboratory Base of Eco-chemical Engineering College of chemical Engineering Qingdao University of Science and TechnologyQingdao266042China key laboratory for green chemical technology of ministry of education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China

Electrocatalytic oxygen reduction(ORR)via the 2e−pathway to form H_(2)O_(2) in acidic medium has attracted extensive attention.However,the low activity,insufficient selectivity and high cost of catalysts have been the bottlenecks.Herein,CoSe_(2) with abundant Se deficiency was synthesized by a simple hydrothermal method,and the addition of NaBH4-induced CoSe_(2) phase transition from orthorhombic to cubic phase with more Se deficiency.The cubic phase CoSe_(2) with abundant Se deficiency can effectively regulate the surface electronic structure with suitable binding energies of*OOH and*O,which shows high activity,selectivity and long-term stability for acidic ORR to H_(2)O_(2).The onset potential is as low as 0.73 V vs.reversible hydrogen electrode(RHE),the H_(2)O_(2) selectivity is 84%(0 V vs.RHE),and the average electron transfer number is about 2.3.Furthermore,the H_(2)O_(2) yield measured using a flow cell is as high as 115.92 mmol·gcat.^(−1)·h^(−1) and the Faradaic efficiency is 70%at 0 V vs.RHE,which presents high potential in electrocatalytic acidic ORR to H_(2)O_(2) and organic pollutant degradation using the electron-Fenton process.

关键词： Se defected CoSe_(2) Crystal phase transition Electrocatalysis Acidic oxygen reduction Hydrogen peroxide

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Engineering oxygen vacancies on Tb-doped ceria supported Pt catalyst for hydrogen production through steam reforming of long-chain hydrocarbon fuels

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Chinese Journal of chemical Engineering 2024年第4期68卷 181-192页

作者： Zhourong Xiao Changxuan Zhang Peng Li Desong Wang Xiangwen Zhang Li Wang Jijun Zou Guozhu Li State key laboratory of Metastable Materials Science and technology(MMST) Hebei Key Laboratory of Applied ChemistryCollege of Environmental and Chemical EngineeringYanshan UniversityQinhuangdao 066004China key laboratory for green chemical technology of ministry of education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Steam reforming of long-chain hydrocarbon fuels for hydrogen production has received great attention for thermal management of the hypersonic vehicle and fuel-cell application.In this work,Pt catalysts supported on CeO_(2)and Tb-doped CeO_(2)were prepared by a precipitation method.The physical structure and chemical properties of the as-prepared catalysts were characterized by powder X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Raman spectroscopy,H_(2)temperature programmed reduction,and X-ray photoelectron spectroscopy.The results show that Tb-doped CeO_(2)supported Pt possesses abundant surface oxygen vacancies,good inhibition of ceria sintering,and strong metal-support interaction compared with CeO_(2)supported Pt.The catalytic performance of hydrogen production via steam reforming of long-chain hydrocarbon fuels(n-dodecane)was tested.Compared with 2Pt/CeO_(2),2Pt/Ce_(0.9)Tb_(0.1)O_(2),and 2Pt/Ce_(0.5)Tb_(0.5)O_(2),the 2Pt/Ce_(0.7)Tb_(0.3)O_(2)has higher activity and stability for hydrogen production,on which the conversion of n-dodecane was maintained at about 53.2%after 600 min reaction under 700℃at liquid space velocity of 9 ml·g^(-1)·h^(-1).2Pt/CeO_(2)rapidly deactivated,the conversion of n-dodecane was reduced to only 41.6%after 600 min.

关键词： Steam reforming n-Dodecane Hydrogen production Pt-based catalyst Oxygen vacancy CeO_(2)

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Synthesis of Organic-Inorganic Hybrid Aluminum Hypophosphite Microspheres Flame Retardant and Its Flame Retardant Research on Thermoplastic Polyurethane

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Journal of Wuhan University of technology(Materials Science) 2024年第1期39卷 221-233页

作者：刘生鹏 XU Zhi ZHANG Xinyuan WEI Huan XIONG Yun DING Yigang HUANG Wenbo 许莉莉 Engineering Research Center of Phosphorus Resources Development and Utilization of ministry of education Key Laboratory for Green Chemical Process of Ministry of EducationSchool of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhan 430205China Hubei Three Gorges laboratory Yichang 443007China School of technology Materials Science and Engineering Wuhan Institute of TechnologyWuhan 430205China

Aluminum hypophosphite microspheres(AHP) were synthesized by hydrothermal method using NaH2PO2·H2O and AlCl3·6H2O as raw materials, and then the AHP microspheres were polymerized by surface polymerization of micro-nanospheres with cyclic cross-linked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol)(PZS). A new organic-inorganic poly(phosphonitrile)-modified aluminum hypophosphite microspheres(PZS-AHP) were synthesized by encapsulation and applied to flame retardant thermoplastic polyurethane(TPU). The microstructure and chemical composition of the PZS-AHP microsphere were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray spectroscopy. The thermal stability of PZS-AHP microsphere was explored with thermogravimetric analysis. Thermogravimetric data indicate that the PZS-AHP microspheres have excellent thermal stability. The thermal and flame-retarding properties of the TPU composites were evaluated by thermogravimetric(TG), limited oxygen index tests(LOI), and cone calorimeter test(CCT). The TPU composite achieved vertical burning(UL-94) V-0 grade and LOI value reached 29.2% when 10 wt% PZS-AHP was incorporated. Compared with those of pure TPU, the peak heat release rate(pHRR) and total heat release(THR) of TPU/10%PZS-AHP decreased by 82.2% and 42.5%, respectively. The results of CCT indicated that PZS-AHP microsphere could improve the flame retardancy of TPU composites.

关键词： polyphosphazene thermoplastic polyurethane flame retardancy aluminum hypophosphite surface polymerization

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Porous metal oxides in the role of electrochemical CO_(2) reduction reaction

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Journal of Energy Chemistry 2024年第1期88卷 373-398,I0009页

作者： Ziqi Zhang Jinyun Xu Yu Zhang Liping Zhao Ming Li Guoqiang Zhong Di Zhao Minjing Li Xudong Hu Wenju Zhu Chunming Zheng Xiaohong Sun School of chemical Engineering and technology Tianjin Key Laboratory of Green Chemical Technology and Process EngineeringState Key Laboratory of Separation Membrane and Membrane ProcessesTiangong UniversityTianjin 300387China School of Materials Science and Engineering Key Laboratory of Advanced Ceramics and Machining TechnologyMinistry of EducationTianjin UniversityTianjin 300072China

The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.

关键词： CO_(2)reduction Carbon dioxide Transformation Porous metal oxides Electrocatalysis

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Unveiling the geometric site dependent activity of spinel Co_(3)O_(4)for electrocatalytic chlorine evolution reaction

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Journal of Energy Chemistry 2024年第5期92卷 95-103页

作者： Linke Cai Yao Liu Jingfang Zhang Qiqi Jia Jiacheng Guan Hongwei Sun Yu Yu Yi Huang key laboratory of Pesticide&chemical Biology of ministry of education Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction of Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhan 430079HubeiChina key laboratory of green chemical Engineering Process of ministry of education Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationHubei Key Laboratory of Novel Reactor and Green Chemical TechnologySchool of Chemical Engineering&PharmacyWuhan Institute of TechnologyWuhan 430205HubeiChina College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108FujianChina School of Chemistry and chemical Engineering Anhui UniversityHefei 230601AnhuiChina

Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.

关键词： Chlorine evolution reaction Geometry effects Active chlorine Electronic configuration optimization Spinel oxides

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Confinement of ionomer for electrocatalytic CO2 reduction reaction via efficient mass transfer pathways

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National Science Review 2024年第2期11卷 168-176页

作者： Xiaowei Du Peng Zhang Gong Zhang Hui Gao Lili Zhang Mengmeng Zhang Tuo Wang Jinlong Gong School of chemical Engineering and technology Key Laboratory for Green Chemical Technology of the Ministry of Education Tianjin University Collaborative Innovation Center of chemical Science and Engineering(Tianjin) National Industry-education Platform of Energy Storage Tianjin University Joint School of the National University of Singapore and Tianjin University International Campus of Tianjin University Haihe laboratory of Sustainable chemical Transformations

Gas diffusion electrodes（GDEs） mediate the transport of reactants, products and electrons for the electrocatalytic CO2reduction reaction（CO2RR） in membrane electrode assemblies. The random distribution of ionomer, added by the traditional physical mixing method, in the catalyst layer of GDEs affects the transport of ions and CO2. Such a phenomenon results in elevated cell voltage and decaying selectivity at high current densities. This paper describes a pre-confinement method to construct GDEs with homogeneously distributed ionomer, which enhances mass transfer locally at the active centers. The optimized GDE exhibited comparatively low cell voltages and high CO Faradaic efficiencies（FE > 90%） at a wide range of current densities. It can also operate stably for over 220 h with the cell voltage staying almost unchanged. This good performance can be preserved even with diluted CO2feeds, which is essential for pursuing a high single-pass conversion rate. This study provides a new approach to building efficient mass transfer pathways for ions and reactants in GDEs to promote the electrocatalytic CO2RR for practical applications.

关键词： CO2 electroreduction gas diffusion electrode mass transfer ionomer Ag catalyst

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