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Enhanced catalytic performance for selective oxidation of propene with O2 over bimetallic Au-Cu/SiO_(2) catalysts

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Rare Metals 2021年第5期40卷 1056-1066页

作者： Xin guo Xue-Quan Sun Yun guo yang-long guo Yun-Song Wang Li Wang Wang-Cheng Zhan Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Au-Cu bimetallic nanoparticles with uniform size,shape,and compositions were synthesized by wet chemistry method,and then the Au-Cu/SiO_(2) catalyst supported on SiO_(2) was ***,their catalytic activity for the selective oxidation of propene to acrolein using O_(2) as an oxidant was *** bimetallic catalyst shows a significantly enhanced catalytic performance comparing with Au and Cu monometallic *** of the materials and kinetic study was conducted to explore the cooperating mechanism of Au and Cu for improving the catalytic activity of the bimetallic *** component can segregate to the alloy surface and the Au-Cu alloy transferred to Au-CuO core/shell structure after annealing during the preparation *** on the Mars-van Krevelen mechanism for the selective oxidation of propene over the prepared catalysts,the coexistence of CuO can promote the adsorption and activation of O_(2).Meanwhile,the electrons transfer from Au to Cu in the catalyst can facilitate the adsorptions of both oxygen on CuO sites and propene on Au *** combined effects of the above two aspects result in the high catalytic activity of the Au-Cu/SiO_(2) catalyst for selective oxidation of propene to acrolein,compared to the Au/SiO_(2) and CuO/SiO_(2) catalysts.

关键词： Bimetallic nanoparticles Core-shell structure Selective oxidation of propene Acrolein Synergistic effect

Studies on Temporal and Spatial Variations of Phytoplankton in Lake Chaohu

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Journal of Integrative Plant Biology 2007年第4期49卷 409-418页

作者： Dao-Gui Deng Ping Xie Qiong Zhou Hua yang long-Gen guo Donghu Experimental Station of Lake Ecosystems State Key Laboratory for Freshwater Ecology and Biotechnology of China Institute of Hydrobiology the Chinese Academy of Sciences Wuhan 430072 China

Temporal and spatial variations of the phytoplankton assemblage in Lake Chaohu, a large shallow eutrophic lake in China, were studied from September 2002 to August 2003. A total of 191 phytoplankton species was identified, among which Chlorophytes （101） ranked the first, followed by Cyanophytes （46） and Bacillariophytes （28）. On aver- age over the entire lake, the maximum total algal biomass appeared in June （19.70 mg/L） with a minimum （5.05 mg/ L） in November. In terms of annual mean biomass, cyanobacteria contributed 45.43% to total algal biomass, followed by Chlorophytes （27.14%）, and Bacillariophytes （20.6%）. When nitrate （NOs-N） and ammonium （NH4-N） concentrations dropped in spring, fixing-nitrogen cyanobacterium （Anabaena） developed quickly and ranked the first in terms of biomass in summer. It is likely that dominance of zooplanktivorous fish and small crustacean zooplankton favored the development of the inedible filamentous or colony forming cyanobacteria. The persistent dominance of cyanobacteria throughout all seasons may indicate a new tendency of the response of phytoplankton to eutrophication in Lake Chaohu.

关键词： cyanobacterial blooms eutrophication Lake Chaohu phytoplankton zooplankivorous fish.

Surface pits stabilized Au catalyst for low-temperature CO oxidation

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Rare Metals 2022年第9期41卷 3060-3068页

作者： Ya-Feng Cai Chen Fei Cheng Zhang Jie yang Li Wang Wang-Cheng Zhan yang-long guo Xiao-Ming Cao Xue-Qing Gong Yun guo Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China

Development of active and stable catalysts for low-temperature CO oxidation has long been regarded as a hot *** this contribution,we used CeO_(2) with high-density surface pits as support to prepare an active and stable Au/CeO_(2) catalyst by an adsorption-deposition *** obtained 0.05 wt%Au/CeO_(2)-TD(where TD represents thermal decomposition)can maintain its activity at 80℃ for more than 20 h or even after calcination at 800℃ for 2 *** characterization results showed that the high-density surface pits on CeO_(2)-TD play a decisive role in the stabilization of Au and enhancement of the redox *** work may provide a new strategy to improve the stability of supported metal catalysts by a simple and conventional method.

关键词： Au catalyst CeO_(2) Surface defect Stability CO oxidation

Synergistic effect of bimetallic RuPt/TiO_(2) catalyst in methane combustion

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Rare Metals 2023年第1期42卷 165-175页

作者： Shi-Ying Cao Fan Ye Ni-Ni Zhang yang-long guo Yun guo Li Wang Sheng Dai Wang-Cheng Zhan Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Centre Institute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China

Designing metal compounds based on their structure and chemical composition is essential in achieving desirable performance in methane oxidation,because of the synergistic effect between different metal ***,a bimetallic Ru-Pt catalyst on TiO_(2) support(RuPt-O/TiO_(2)) was prepared by in situ reduction followed by calcination in *** with monometallic catalysts(Ru-O/TiO_(2) and Pt-O/TiO_(2)),the synergistic effect of mixed metals endowed bimetallic catalysts with excellent stability and outstanding performance in methane oxidation,with a reaction rate of 13.9×10^(-5)mol^(-1)_(CH_(4))·g^(-1)_(Ru+Pt)·s^(-1)at 303℃.The varied characterization results revealed that among the bimetallic catalysts,RuO_(2)was epitaxially grown on the TiO_(2) substrate owing to lattice matching between them,and part of the PtO_(x) adhered to the RuO_(2) surface,in addition to a single PtO_(x) nanoparticle with 4 nm in ***,Pt mainly existed in the form of Pt2+and Pt4+and a small amount of zero valence in the bimetallic catalyst,prompting the adsorption and activation of methane as the first and rate-controlling step for CH_(4) *** importantly,the RuO_(2) species provided additional oxygen species to facilitate the redox cycle of the PtO_(x) *** study opens a new route for structurally designing promising catalysts for CH4oxidation.

关键词： Synergistic effect Bimetallic catalyst Methane combustion Redox cycle

Catalytic combustion of vinyl chloride emissions over Co_(3)O_(4) catalysts with different crystallite sizes

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Rare Metals 2021年第4期40卷 817-827页

作者： Wen-Chao Hua Ming-Qi Li yang-long guo Guang-Tao Chai Hao Liu Yun guo Li Wang Wang-Cheng Zhan Key Laboratory for Advanced Materials Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

A series of Co_(3) O_(4) catalysts was prepared by ammonia(Co-AP) and oxalate(Co-OP) precipitation,solgel(Co-SG),and urea hydrothermal(Co-UH) methods,and their physicochemical properties were characterised by numerous techniques including X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen sorption,X-ray photoelectron spectroscopy(XPS),temperature-programmed reduction of H_(2)(H_(2)-TPR),temperature-programmed desorption of O_(2)(O_(2)-TPD),and temperature-programmed desorption of NH_(3)(NH_(3)-TPD).The catalytic activity of each catalyst was estimated for the catalytic combustion of vinyl chloride(VC) *** crystallite size of the Co_(3) O_(4) catalyst was found to be well correlated with the amounts of surface-adsorbed oxygen species and number of acid sites on the catalyst surface,and consequently,determined several physicochemical properties of the *** the catalysts studied here,the Co-AP catalyst exhibits the smallest crystallite size,which increases the specific surface area and the concentration of Co^(2+) on the catalyst ***,in turn,enhances the redox property,oxygen mobility,and the number of acid sites associated with the Co-AP *** fact,the Co-AP catalyst exhibits the best catalytic activity for VC combustion at 360℃and does not produce any chlorinated by-products.

关键词： Catalytic combustion Vinyl chloride Cobalt oxides Crystallite size Preparation methods

Epoxidation of propylene by molecular oxygen over unsupported AgCu_x bimetallic catalyst

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Rare Metals 2015年第7期34卷 477-490页

作者： Xiang Zheng yang-long guo Yun guo Qing Zhang Xiao-Hui Liu Li Wang Wang-Cheng Zhan Guan-Zhong Lu Key Laboratory for Advanced Materials Research Institute of Industrial Catalysis East China University of Science and Technology

The unsupported Cu and Ag catalysts with different oxidation states were prepared, and their catalytic performances for propylene epoxidation were *** metallic Cu catalyst exhibits much higher catalytic activity and propylene oxide(PO) selectivity than Cu2 O and Cu O *** Cu0 species are the main active sites for propylene epoxidation, but Cu2 O and Cu O species are in favor of CO2 and acrolein *** PO selectivity of 54.2 % and propylene conversion of 2.6 % can be achieved over the metallic Cu catalyst at 160 °C in initial stage, but metallic Cu catalyst would be oxidized to Cu2 O during propylene epoxidation, resulting in a sharp decrease in the PO selectivity and propylene *** Ag Cuxbimetallic catalysts were *** is found that adding Ag to the metallic Cu catalysts can prevent the oxidation of Cu and make Ag Cuxbimetallic catalysts more stable under the condition of propylene *** Ag/Cu molar ratio can remarkably affect the catalytic performance of Ag Cuxcatalyst and the selectivity to PO and *** Ag Cuxwas supported on MOx-modified a-Al2O3, its catalytic performance can be improved and has a close relationship with the acid–base property of support.

关键词： Epoxidation of propylene Propylene oxide Molecular

Tuning performance of Pd/Sn_(0.9)Ce_(0.1)O_2 catalyst for methane combustion by optimizing calcination temperature of support

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Rare Metals 2019年第2期38卷 107-114页

作者： Kai Shen Jia-Pan Lin Qian Xia Lu Dai guo-Jun Zhou yang-long guo Guan-Zhong Lu Wang-Cheng Zhan Technology Center China Tobacco Zhejiang Industrial Co.Ltd. Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis East China University of Science and Technology

A series of 0.2 wt% Pd/Sn_(0.9)Ce_(0.1)O_2 catalysts were prepared by impregnation method based on the presynthesis of Sn_(0.9)Ce_(0.1)O_2 support prepared by co-precipitation method, and then characterized by Brunauer–Emmett–Teller(BET), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), Raman, CO chemical adsorption and hydrogen temperature-programmed reduction(H_2-TPR) techniques. The effect of calcination temperature of the composite oxide support on the catalytic performances of the Pd/Sn_(0.9)Ce_(0.1)O_2 catalyst for the CH_4 total oxidation was studied. It is found that the catalytic activity of the Pd/Sn_(0.9)Ce_(0.1)O_2 catalyst increases with the increase in calcination temperature of the Pd/Sn_(0.9)Ce_(0.1)O_2 support. The 0.2 wt% Pd/Sn_(0.9)Ce_(0.1)O_2/1100 catalyst(the Pd/Sn_(0.9)Ce_(0.1)O_2 support was calcined at 1100 ℃) exhibits the best reactive activity(T_(10)= 255 ℃). The excellent activity of the 0.2 wt% Pd/Sn_(0.9)Ce_(0.1)O_2/1100 catalyst should be attributed to the high reducibility of PdO, the excellent oxygen mobility of the support and the high content of active Pd^(2+) species on the Pd/Sn_(0.9)Ce_(0.1)O_2 catalyst.

关键词： Catalytic combustion Methane PdO SnxCe1-xO2 Calcination temperature

Catalytic activity of Cu-SSZ-13 prepared with different methods for NH_3-SCR reaction

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Rare Metals 2019年第3期38卷 210-220页

作者： Meng-Jie Han Yun-Lei Jiao Chun-Hong Zhou yang-long guo Yun guo Guan-Zhong Lu Li Wang Wang-Cheng Zhan Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis East China University of Science and Technology

A series of Cu-SSZ-13 catalysts with the same Cu loading were prepared by different methods of incipient wetness impregnation [Cu-SSZ-13(IWI)], ion exchange[Cu-SSZ-13(IE)] and hydro-thermal synthesis [Cu-SSZ-13(HTS)]. Their activity for selective catalytic reduction of nitrogen oxides(NO_x) with NH3 was determined. The results show that the Cu-SSZ-13(HTS) catalyst exhibits a better ammonia selective catalytic reduction(NH3-SCR)activity compared with the other two catalysts, over which more than 90% NO conversion is obtained at 215-600℃under the space velocity of 180,000 h^(-1). The characterization results reveal that the Cu-SSZ-13(HTS) catalyst possesses more amount of stable Cu^(2+) in the six-membered ring and high ability for NH3 and NO adsorption, leading to its high NH3-SCR activity, although this catalyst has low surface area. On the other hand, the activity of Cu-SSZ-13(IE) catalyst is almost the same as that of Cu-SSZ-13(IWI) catalyst at the temperature lower than 400 ℃, but the activity of the former is much higher than that of the latter at > 400 ℃ due to the high activity of Cu-SSZ-13(IWI) catalyst for NH3 oxidation.

关键词： SSZ-13 zeolite Selective catalytic reduction Nitrogen oxides Preparation method Cu2+

The complex effects of miR-146a in the pathogenesis of Alzheimer's disease

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Neural Regeneration Research 2025年第5期20卷 1309-1323页

作者： Yunfan long Jiajia Liu Yu Wang Haidong guo guohong Cui Department of Neurology Shanghai No.9 People’s HospitalShanghai Jiaotong University School of MedicineShanghaiChina Academy of Integrative Medicine Shanghai University of Traditional Chinese MedicineShanghaiChina School of Integrative Medicine Shanghai University of Traditional Chinese MedicineShanghaiChina Department of Neurology Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese MedicineShanghaiChina

Alzheimer's disease is a neurodegenerative disorder characterized by cognitive dysfunction and behavioral *** plaques formed through the extracellular deposition of amyloid-βproteins,as well as neurofibrillary tangles formed by the intracellular deposition of hyperphosphorylated tau proteins,comprise two typical pathological features of Alzheimer's *** symptomatic treatment,there are no effective therapies for delaying Alzheimer's disease ***(miR)are small,non-coding RNAs that negatively regulate gene expression at the transcriptional and translational levels and play important roles in multiple physiological and pathological ***,miR-146a,a NF-κB-regulated gene,has been extensively implicated in the development of Alzheimer's disease through several *** has demonstrated substantial dysregulation of miR-146a both during the initial phases and throughout the progression of this *** R-146a is believed to reduce amyloid-βdeposition and tau protein hyperphosphorylation through the TLR/IRAK1/TRAF6 pathway;however,there is also evidence supporting that it can promote these processes through many other pathways,thus exacerbating the pathological manifestations of Alzheimer's *** has been widely reported that miR-146a mediates synaptic dysfunction,mitochondrial dysfunction,and neuronal death by targeting m RNAs encoding synapticrelated proteins,mitochondrial-related proteins,and membrane proteins,as well as other *** the impact on glial cells,miR-146a also exhibits differential *** one hand,it causes widespread and sustained inflammation through certain pathways,while on the other hand,it can reverse the polarization of astrocytes and microglia,alleviate neuroinflammation,and promote oligodendrocyte progenitor cell differentiation,thus maintaining the normal function of the myelin sheath and exerting a protective effect on *** this review,we provide a

关键词： Alzheimer's disease amyloid-β glial cells microRNAs miR-146a neuroinflammatory