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Highly selective electrosynthesis of 3,4-dihydroisoquinoline accompanied with hydrogen production over three-dimensional hollow CoNi-based microarray electrocatalysts

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Nano Research 2024年第4期17卷 2509-2519页

作者： Yu Xin liyu Chen yingwei li Kui Shen Guangdong Provincial Key Lab for Green Chemical Product Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Electrocatalytic oxidation reaction of biomass-based derivatives is an excellent candidate to replace water oxidation for obtaining both value-added products and hydrogen(H_(2)),but the exploration of competent electrocatalysts is still highly ***,two new types of three-dimensional self-supported hollow microarrays containing CoNi layered double hydroxide(CoNi-LDH)and N-doped carbon nanosheets decorated with CoNi alloyed nanoparticles(CoNi-NC)on carbon cloth(CC)are prepared,which are further used as efficient electrocatalysts for tetrahydroisoquinoline(THIQ)electrooxidation and hydrogen evolution reaction(HER),*** demonstrate that the Co-modulated electronic environment for Ni(II)/Ni(Ⅲ)redox-looping in CoNi-LDH is the main factor to boost the selectivity of 3,4-dihydroisoquinoline(DHIQ)for the indirect electrooxidation process of *** functional theory(DFT)calculations reveal that the Ni(Ⅲ)/Co(Ⅲ)dual sites of CoNi-LDH exhibit enhanced adsorption for THIQ but poorer adsorption for DHIQ compared to pure Co(Ⅲ)or Ni(Ⅲ).Therefore,the Ni(Ⅲ)/Co(Ⅲ)dual sites can effectively inhibit the peroxidation of DHIQ to isoquinoline(IQ)over CoNi-LDH,thus improving the selectivity of DHIQ to nearly 100%,much higher than that of its pure Ni ***,CC@CoNi-NC can deliver high HER activity with low overpotential(40 mV@10 mA·cm^(-2))and high exchange current density(3.08 mA·cm^(-2)).Impressively,the assembled flow-cell device with CC@CoNi-LDH anode and CC@CoNi-NC cathode only requires low cell voltage and electricity consumption of 1.6 V and 3.50 kWh per cubic meter of H_(2)(@25 mA·cm^(-2)).

关键词： highly selective electrosynthesis dihydroisoquinolines hydrogen evolution reaction metal-organic frameworks hollow microarrays

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Scalable synthesis of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures from MOFs for pH-universal hydrogen evolution reaction

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Science China Chemistry 2022年第3期65卷 619-629页

作者： Zhiqiao Wang Kui Shen liyu Chen yingwei li Key Laboratory of Fuel Cell Technology of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Developing low-cost but efficient hydrogen evolution reaction(HER)electrocatalysts over whole pH values is a significant but daunting task for the large-scale application of electrochemical hydrogen ***,we develop,for the first time,a scalable MOF-assisted strategy for the fabrication and microstructural optimization of multi-shelled hollow N-doped carbon nanosheet arrays with confined Co/CoP heterostructures on carbon cloth(Co/CoP@NC/CC)for boosting HER *** key to this strategy is the step-by-step epitaxial growth of unprecedented multilayer ZIF-L arrays on carbon cloth,which are subsequently pyrolyzed and controllably phosphorized to achieve the precise control over the shell number and nanoarchitectures of the Co/CoP@NC/***,the HER performances can be significantly enhanced by increasing hollow shell number,and the optimal triple-shelled hollow Co/CoP@NC/CC exhibits low overpotentials of 86,78 and 145 mV in acidic,alkaline and neutral media to deliver a current density of 10 mA cm^(-2),respectively,ranking as one of the best Co-based HER electrocatalysts over whole pH *** DFT calculations suggest that the Co/CoP heterostructures can effectively boost the cleavage of H–OH to generate protons and optimize the adsorption energy of hydrogen(ΔG_(H*)),which,together with the large electrode/electrolyte interface and accelerated charge/mass transfer of multi-shelled hollow array structure as well as the good conductivity and dispersity,are responsible for the remarkably improved HER *** study not only provides a new toolbox for enriching the family of multi-shelled nanoarchitecture materials,but also points out a general and effective route to develop highly efficient self-supported electrode materials for energy-related applications and beyond.

关键词： multi-shelled hollow arrays metal-organic frameworks multilayer ZIF-L arrays Co/CoP heterostructures hydrogen evolution reaction

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N-doped nanocarbon embedded in hierarchically porous metal-organic frameworks for highly efficient CO_(2) fixation

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Science China Chemistry 2022年第7期65卷 1411-1419页

作者： Fengfeng Chen Kui Shen liyu Chen yingwei li Guangdong Provincial Key Laboratory of Fuel Cell Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

The rational integration of multi-functional components with metal–organic frameworks(MOFs) to form MOF-based catalysts can often afford enhanced catalytic activity for specific reactions. Herein, we propose a novel strategy for the synthesis of hierarchically porous MOFs(e.g., MIL-101)-encapsulated N-doped nanocarbon(CN@MIL) by controlled pyrolysis of ionic liquids@MIL-101 precursors(ILs@MIL). The obtained CN@MIL composites not only possess abundant enlarged mesopores,but also show multi-active sites without the sacrifice of their structure stability. The CN@MIL can efficiently facilitate the mass transfer of substrates, exhibiting excellent catalytic performance in the synthesis of cyclic carbonates from epoxides and CO_(2) under mild and co-catalyst-free conditions(i.e., 90 ℃ and ambient pressure of CO_(2)). Furthermore, the multi-active Lewis acid sites and nucleophilic sites(Br ions) as well as the strong affinity of catalysts toward CO_(2)also contribute to the excellent catalytic activity of the CN@MIL. This study might open a new avenue for the rational design of MOF-based composites by employing ILs@MOF as precursors for advanced heterogeneous catalysis.

关键词： metal-organic frameworks N-doped nanocarbons encapsulation hierarchical porosity CO_(2)fixation

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Encapsulation of ultrafine Pd nanoparticles within the shallow layers of UiO-67 for highly efficient hydrogenation reactions

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Science China Chemistry 2021年第1期64卷 109-115页

作者： Zhiming Cui Ting Fan liyu Chen Ruiqi Fang Chuanmao li yingwei li State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China Guangzhou Keneng Cosmetics Scientific Research Co. Lid.Guangzhou 510800China

Metal-organic frameworks(MOFs)have been used to encapsulate active metal nanoparticles(MNPs)to fabricate MNPs@MOFs composites with high catalytic ***,the diffusion of reactants and the accessibility of MNPs located in the center of MOFs may be hindered due to the inherent microporous structures of MOFs,which would affect the catalytic activities of ***,we report a solvent assisted ligand exchange-hydrogen reduction(SALE-HR)strategy to selectively encapsulate ultrafine MNPs(Pd or Pt)within the shallow layers of a MOF,i.e.,*** particle sizes of the encapsulated MNPs and the thickness of the MNPs-embedded layers can be adjusted easily by controlling the SALE conditions(*** and temperature).Crucially,the LE-Pd@UiO-80-0.5 composite with the thinnest Pd-embedded layers displays remarkable catalytic efficiency with a high turnover frequency(TOF)value of 600 h^-1towards hydrogenation of nitrobenzene under 1 atm H_2at room *** results indicate that the catalytic efficiency and the utilization of MNPs can be enhanced by compactly encapsulating MNPs within the shallow layers of MOFs as close to their outer surfaces as possible,owing to the short masstransfer distance and enhanced accessibility of overall MNPs.

关键词： Metal-organic frameworks metal nanoparticles heterogeneous catalysis encapsulation hydrogenation

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Wind power forecasting based on new hybrid model with TCN residual modification

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Energy and AI 2022年第4期10卷 136-148页

作者： Jiaojiao Zhu liancheng Su yingwei li School of Electrical Engineering Yanshan UniversityQinhuangdaoHebei 066004China School of Information Science and Engineering Yanshan UniversityQinhuangdaoHebei 066004China

Wind energy has been widely utilized to alleviate the shortage of fossil *** wind power is integrated into the power grid on a large scale,the power grid’s stability is severely harmed due to the fluctuating and intermittent properties of wind *** wind power forecasts help to formulate good operational strategies for wind farms.A short-term wind power forecasting method based on new hybrid model is proposed to increase the accuracy of wind power ***,wind power time series are separated using the complete ensemble empirical mode decomposition with adaptive noise method to obtain multiple components,which are then predicted using a support vector regression machine model optimized through using the grid search and cross validation(GridSearchCV)***,a residual modification model based on temporal convolutional network is constructed,and variables with high correlation are selected as the input features of the model to predict the residuals of wind ***,the prediction accuracy of the proposed method is compared to other models using the actual wind power data of the wind farm to demonstrate the validity of the described method,and the results reveal that the proposed method has better prediction performance.

关键词： Wind power forecast Hybrid model Temporal convolutional network Residual modification

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Preparation of sodium molybdate from molybdenum concentrate by microwave roasting and alkali leaching

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 91-105页

作者： Fengjuan Zhang Chenhui liu Srinivasakannan Chandrasekar yingwei li Fuchang Xu School of Chemistry and Environment Yunnan Minzu UniversityKunming 650500China Chemical Engineering Department Khalifa UniversityAbu DhabiUAE Yunnan Zhong Tai Technology Co. Ltd.Kunming 650500China Yunnan Yongchang Silicon Industry Co. Ltd.Baoshan 678000China

The preparation process of sodium molybdate has the disadvantages of high energy consumption,low thermal efficiency,and high raw material requirement of molybdenum trioxide,in order to realize the green and efficient development of molybdenum concentrate resources,this paper proposes a new process for efficient recovery of molybdenum from molybdenum concentrate and preparation of sodium molybdate by microwave-enhanced roasting and alkali *** analysis indicated the feasibility of oxidation roasting of molybdenum *** effects of roasting temperature,holding time,and power-to-mass ratio on the oxidation product and leaching product sodium molybdate (Na_(2)MoO_(4)·2H_(2)O) were *** the optimal process conditions:roasting temperature of 700℃,holding time of 110 min,and power-to-mass ratio of 110 W/g,the molybdenum state of existence was converted from MoS_(2) to Mo *** process of preparing sodium molybdate by alkali leaching of molybdenum calcine was investigated,the optimal leaching conditions include a solution concentration of 2.5 mol/L,a liquid-to-solid ratio of 2 mL/g,a leaching temperature of 60℃,and leaching solution termination at pH *** optimum conditions result in a leaching rate of sodium molybdate of 96.24%.Meanwhile,the content of sodium molybdate reaches 94.08wt%after leaching and removing *** and aluminum impurities can be effectively separated by adjusting the pH of the leaching solution with sodium carbonate *** research avoids the shortcomings of the traditional process and utilizes the advantages of microwave metallurgy to prepare high-quality sodium molybdate,which provides a new idea for the highvalue utilization of molybdenum concentrate.

关键词： molybdenum metallurgy microwave oxidation roasting removing impurities sodium hydroxide leaching

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Carbon-based nanoarrays embedded with Ce-doped ultrasmall Co_(2)P nanoparticles enable efficient electrooxidation of 5-hydroxymethylfurfural coupled with hydrogen production

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Science China Chemistry 2023年第7期66卷 2141-2152页

作者： Shangfang Xie Hongchuan Fu liyu Chen yingwei li Kui Shen Guangdong Provincial Key Laboratory of Fuel Cell Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

The electrooxidation of 5-hydroxymethylfurfural(HMFOR)not only offers a green route to attain high-value 2,5-furandicarboxylic acid(FDCA)from biomass,but also is considered as a promising approach to replace the kinetically sluggish OER for future hydrogen ***,we report the construction and structural optimization of Ce-doped ultrasmall Co_(2)P nanoparticles(NPs)in carbon-based nanoarrays to boost HER-coupled *** demonstrate that the electronic structure of Co-based electrocatalysts can be positively regulated by Ce doping and the optimized Ce-Co_(2)P-based electrocatalyst only require a low voltage of 1.20 V *** to achieve 10 m A cm^(-2)for HMFOR with an excellent FDCA Faraday efficiency(FEFDCA)of 98.5%,which are superior to its Ce-free counterpart(1.29 V ***;FEFDCA=83.9%).When being assembled into a HERcoupled HMFOR system,this bifunctional electrocatalyst can achieve 50 m A cm^(-2)with an ultralow voltage of 1.46 V,which is reduced by 210 m Vas compared with that of its Ce-free counterpart(1.67 V).Quasi-operando experiments and DFTcalculations further reveal the significant roles of Ce doping in promoting the charge transfer between active sites and HMF,and reducing the free energy barrier of intermediate(^(*)HMFCA)*** study provides new insights into the underlying mechanisms of Ce doping into metal phosphides for boosting HER-coupled HMFOR,developing a facile methodology to construct efficient electrocatalysts for energy storage/conversion systems.

关键词： ultrasmall Co_(2)P nanoparticles Ce doping nanosheet arrays 5-hydroxymethylfurfural electrooxidation hydrogen evolution reaction

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Facet-selective growth of MOF-on-MOF heterostructures enables etching-free synthesis of highly-open Co/N-doped carbon nanoframes for efficient catalysis

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Science China Chemistry 2022年第12期65卷 2450-2461页

作者： Yaohui Wu liyu Chen Xianfeng Yang yingwei li Kui Shen Guangdong Provincial Key Laboratory of Fuel Cell Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou510640China Analytical and Testing Centre South China University of TechnologyGuangzhou510640China

Highly-open nanoframe structures consisting of interconnected and exposed ridges are highly desirable for achieving efficient catalysis,but preparing them by a facile etching-free methodology is still a very daunting ***,we propose a novel metal-organic framework(MOF)-assisted and etching-free strategy for the construction of Co/N-doped carbon nanoframes with highly-open and precisely-controllable *** strategy is based on the face-selective epitaxial growth of ZIF-67 on the 36{110}facets of 72-facet ZIF-8 to form an unprecedented anisotropic ZIF-67-on-ZIF-8 heterostructure,which is subsequently pyrolyzed under Ar atmosphere to realize a solid-to-frame *** highly-open nanoframe structure enables the substrates to readily penetrate into the catalyst interior and thereby create additional exposed active sites,which together with the good mass transport,high atomic utilization and increased surface area are responsible for its remarkably enhanced catalytic activity for the biomass valorisation when compared with its solid and closed hollow *** study could shed valuable insights into the design and preparation of various highly-open nanoframes with abundant exposed active species by using an etching-free strategy for efficient catalysis and beyond.

关键词： metal-organic frameworks etching-free synthesis highly-open nanoframes pyrolysis efficient catalysis

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Prediction model of microwave calcining of ammonium diuranate using incremental improved back-propagation neural network

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Acta Metallurgica Sinica(English Letters) 2011年第1期24卷 34-42页

作者： yingwei li Bingguo liU Jinhui PENG Wei li Daifu HUANG libo ZHANG Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming 650093 China Key Laboratory of Unconventional Metallurgy Ministry of Education Kunming University of Scienceand Technology Kunming 650093 China No.272 Nuclear Industry Factory China National Nuclear Corporation Hengyang 421002 ChinaMamlscript received 2~~ May 2010 in revised form 17 October 2010

The incremental improved Back-Propagation （BP） neural network prediction model using the Levenberg-Marquardt algorithm based on optimizing theory is put forward, which can solve the problems existing in the process of calcinations for ammonium diuranate （ADU） by microwave heating, such as long testing cycle, high testing quan- tity, difficulty of optimization for process parameters. Many training data probably were offered by the way of increment batch and the limitation of the system mem- ory could make the training data infeasible when the sample scale was large. The prediction model of the nonlinear system is built, which can effectively predict the experiment of microwave calcining of ADU, and the incremental improved BP neural network is very useful in overeoining the local minimum problem, finding the global optimal solution and accelerating the convergence speed.

关键词： Microwave calcinations ADU Increment BP neural network Prediction

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Formation of willow leaf-like structures composed of NH2-MIL68（In） on a multifunctional multiwalled carbon nanotube backbone for enhanced photocatalytic reduction of Cr（VI）

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Nano Research 2017年第10期10卷 3543-3556页

作者： Yunhong Pi Xiyi li Qibin Xia Junliang Wu Zhong li yingwei li Jing Xiao School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control South China University of Technology Guangzhou 510640 China

Efficient separation and transfer of photogenerated electron/hole as well as enhanced visible light absorption play essential roles in photocatalytic reactions. To promote the photocatalytic reduction of Cr（VI）, a toxic heavy metal ion, multiwalled carbon nanotube （MWCNT） was introduced as an electron acceptor into NH2-MIL-68（In）. This led to the growth of a willow leaf-like metal-organic framework （MOF） on an MWCNT backbone forming MWCNT/NH2-MIL-68（In）（PL-1）, which showed a highly efficient transfer of photogenerated carriers. Moreover, MWCNT incorporation introduced more mesopores for Cr（VI） diffusion and enhanced the visible light adsorption without lowering the conduction band position. As a result, the photocatalytic kinetic constant of PL-1 was found to be almost three times higher than that of the parent NH2-MIL-68（In）. Thus, growing MOFs on MWCNTs provides a facile and promising solution for effective remediation of environmental pollution by utilizing solar energy. This work provides the first example of using MWCNT/MOF composites for photocatalytic reactions.

关键词： NH2-MIL-68(In) multiwalled carbon nanotube (MWCNT) photocatalytic reduction Cr(VI)

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