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Designing ultrastable P2/O3-type layered oxides for sodium ion batteries by regulating Na distribution and oxygen redox chemistry
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作者 Jieyou Huang Weiliang Li +3 位作者 Debin Ye Lin Xu Wenwei Wu Xuehang Wu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期466-476,共11页
P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phas... P2/O3-type Ni/Mn-based layered oxides are promising cathode materials for sodium-ion batteries(SIBs)owing to their high energy density.However,exploring effective ways to enhance the synergy between the P2 and 03 phases remains a necessity.Herein,we design a P2/O3-type Na_(0.76)Ni_(0.31)Zn_(0.07)Mn_(0.50)Ti_(0.12)0_(2)(NNZMT)with high chemical/electrochemical stability by enhancing the coupling between the two phases.For the first time,a unique Na*extraction is observed from a Na-rich O3 phase by a Na-poor P2 phase and systematically investigated.This process is facilitated by Zn^(2+)/Ti^(4+)dual doping and calcination condition regulation,allowing a higher Na*content in the P2 phase with larger Na^(+)transport channels and enhancing Na transport kinetics.Because of reduced Na^(+)in the O3 phase,which increases the difficulty of H^(+)/Na^(+) exchange,the hydrostability of the O3 phase in NNZMT is considerably improved.Furthermore,Zn^(2+)/Ti^(4+)presence in NNZMT synergistically regulates oxygen redox chemistry,which effectively suppresses O_(2)/CO_(2) gas release and electrolyte decomposition,and completely inhibits phase transitions above 4.0 V.As a result,NNZMT achieves a high discharge capacity of 144.8 mA h g^(-1) with a median voltage of 3.42 V at 20 mA g^(-1) and exhibits excellent cycling performance with a capacity retention of 77.3% for 1000 cycles at 2000 mA g^(-1).This study provides an effective strategy and new insights into the design of high-performance layered-oxide cathode materials with enhanced structure/interface stability forSIBs. 展开更多
关键词 Sodium-ion batteries P2/o3-type layered oxides Na distribution oxygen redox chemistry Hydrostability
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CO_(2)/C_(3)H_(6)O在金属氧化物耦合吡咯氮生物炭表面的共/竞吸附机理研究
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作者 汪辉春 花昌豪 +4 位作者 陈萍 顾明言 龚成 邹帅 汪一 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2024年第2期206-217,共12页
本研究采用密度泛函理论,通过比较吸附量、吸附能以及态密度和电荷差分密度的分析,探究了不同金属氧化物耦合吡咯氮生物炭(CN5@MOx,MOx=ZnO、CaO、Na2O)表面CO_(2)与C_(3)H_(6)O(CO_(2)&C_(3)H_(6)O)的吸附机理。首先从CO_(2)/C_(3)... 本研究采用密度泛函理论,通过比较吸附量、吸附能以及态密度和电荷差分密度的分析,探究了不同金属氧化物耦合吡咯氮生物炭(CN5@MOx,MOx=ZnO、CaO、Na2O)表面CO_(2)与C_(3)H_(6)O(CO_(2)&C_(3)H_(6)O)的吸附机理。首先从CO_(2)/C_(3)H_(6)O单组分方面计算了其在CN5@MOx表面吸附量和吸附能,计算结果表明,在333 K、100 kPa时CN5@Na2O表面对CO_(2)/C_(3)H_(6)O单组分吸附量分别为3.65、15.34 mmol/g,吸附能分别为-145.86、-132.47 kJ/mol,均高于CO_(2)/C_(3)H_(6)O单组分在CN5@CaO及CN5@ZnO表面吸附。得出Na2O掺杂吡咯氮生物炭对CO_(2)/C_(3)H_(6)O单组分吸附效果最优。进一步研究了CO_(2)&C_(3)H_(6)O在CN5@MOx表面共/竞吸附及机理。计算结果表明,CO_(2)&C_(3)H_(6)O在CN5@Na2O、CN5@CaO、CN5@ZnO表面吸附存在临界温度(分别为333、353、393 K),超过临界温度以后CO_(2)&C_(3)H_(6)O共存体系在CN5@MOx表面吸附量较CO_(2)/C_(3)H_(6)O单组分有所提高。CO_(2)&C_(3)H_(6)O在CN5@Na2O、 CN5@CaO、 CN5@ZnO表面吸附能分别比CO_(2)或C_(3)H_(6)O单组分吸附时至少高141.59、112.77、31.75 kJ/mol,CN5@MOx表面对CO_(2)和C_(3)H_(6)O的吸附表现为协同促进作用,且CN5@Na2O对CO_(2)&C_(3)H_(6)O共同吸附效果最佳。采用电荷差分密度和态密度分析CO_(2)&C_(3)H_(6)O在CN5@MOx表面协同吸附作用机理,得出CO_(2)的吸附作用力是通过C_(3)H_(6)O与CO_(2)的间接相互作用产生的,Na2O中Na与C_(3)H_(6)O电子云重叠,发生电荷转移,增强了两者间相互作用力,CN5@Na2O表面C_(3)H_(6)O与CN5在p轨道主要共振峰结合能较CN5@ZnO低了3.43 eV,使得C_(3)H_(6)O在CN5@Na2O表面吸附最稳定。 展开更多
关键词 吡咯氮生物炭 金属氧化物 Co_(2) C_(3)H_(6)o
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Dielectric barrier discharge plasma synthesis of Ag/γ-Al_(2)O_(3) catalysts for catalytic oxidation of CO
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作者 陶云明 胥月兵 +4 位作者 常宽 陈美玲 Sergey A STAROSTIN 许虎君 林良良 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第8期113-121,共9页
In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can r... In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can reduce silver ions to generate crystalline silver nanoparticles(Ag NPs)of good dispersion and uniformity on the alumina surface,leading to the formation of Ag/γ-Al_(2)O_(3)catalysts in a green manner without traditional chemical reductants.Ag/γ-Al_(2)O_(3)exhibited good catalytic activity and stability in CO oxidation reactions,and the activity increased with increase in the Ag content.For catalysts with more than 2 wt%Ag,100%CO conversion can be achieved at 300°C.The catalytic activity of the Ag/γ-Al_(2)O_(3)catalysts is also closely related to the size of theγ-alumina,where Ag/nano-γ-Al_(2)O_(3)catalysts demonstrate better performance than Ag/micro-γ-Al_(2)O_(3)catalysts with the same Ag content.In addition,the catalytic properties of plasma-generated Ag/nano-γ-Al_(2)O_(3)(Ag/γ-Al_(2)O_(3)-P)catalysts were compared with those of Ag/nano-γ-Al_(2)O_(3)catalysts prepared by the traditional calcination approach(Ag/γ-Al_(2)O_(3)-C),with the plasma-generated samples demonstrating better overall performance.This simple,rapid and green plasma process is considered to be applicable for the synthesis of diverse noble metal-based catalysts. 展开更多
关键词 DBD plasma plasma nanofabrication noble metal nanoparticles Co oxidation Ag/-Al2o3 catalysts
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Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al_2O_3 catalysts 被引量:2
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作者 Armin Moniri S.Mehdi Alavi Mojgan Rezaei 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2010年第6期638-641,共4页
Ni/α-Al2O3 catalysts were found to be active in the temperature range 600 ~ 900℃ for both CO2 reforming and partial oxidation of methane.The effects of Ni loading,reaction temperature and feed gas ratio for the com... Ni/α-Al2O3 catalysts were found to be active in the temperature range 600 ~ 900℃ for both CO2 reforming and partial oxidation of methane.The effects of Ni loading,reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated.Catalysts of xwt%Ni/α-Al2O3(x=2.5,5,8 and 12) were prepared by wet impregnating the calcined support with a solution of nickel nitrate.XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst,as compared with the other prepared catalyst samples.An increase of the Ni loading to more than 5wt% led to a reduction in the Ni dispersion.In addition,by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction,the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed. 展开更多
关键词 o2 carbon dioxide (Co2 METHANE Ni/α-Al2o3 catalysts combined reaction
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Fabrication of Gd_(2)O_(3)-doped CeO_(2)thin films through DC reactive sputtering and their application in solid oxide fuel cells 被引量:2
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作者 Fuyuan Liang Jiaran Yang +1 位作者 Haiqing Wang Junwei Wu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第6期1190-1197,共8页
Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscalin... Physical vapor deposition(PVD)can be used to produce high-quality Gd_(2)O_(3)-doped CeO2(GDC)films.Among various PVD methods,reactive sputtering provides unique benefits,such as high deposition rates and easy upscaling for industrial applications.GDC thin films were successfully fabricated through reactive sputtering using a Gd_(0.2)Ce_(0.8)(at%)metallic target,and their application in solid oxide fuel cells,such as buffer layers between yttria-stabilized zirconia(YSZ)/La0.6Sr0.4Co0.2Fe0.8O_(3−δ)and as sublayers in the steel/coating system,was evaluated.First,the direct current(DC)reactive-sputtering behavior of the GdCe metallic target was determined.Then,the GDC films were deposited on NiO-YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films.The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering.Furthermore,the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer.In addition,the insertion of a GDC sublayer between the SUS441 interconnects and the Mn-Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures,according to the area-specific resistance tests. 展开更多
关键词 solid oxide fuel cell physical vapor deposition Gd2o3-doped Ceo_(2) metallic interconnects electrical conductivity
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Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content 被引量:1
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作者 Thongsuk Sichumsaeng Atchara Chinnakorn +3 位作者 Ornuma Kalawa Jintara Padchasri Pinit Kidkhunthod Santi Maensiri 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第10期1887-1896,共10页
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X... The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors. 展开更多
关键词 sodium nickel manganese oxide mixed P2/o3-type Na-excess content sol-gel method electrospinning method electrochemical properties
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Morphology and Frictional Characteristics Under Electrical Currents of Al_2O_3/Cu Composites Prepared by Internal Oxidation 被引量:7
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作者 刘瑞华 宋克兴 +3 位作者 贾淑果 徐晓峰 郜建新 国秀花 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第3期281-288,共8页
Two Al2O3/Cu composites containing 0.24 wt.% Al2O3 and 0.60 wt.% Al2O3 separately are prepared by internal oxidation. Effects of sliding speed and pressure on the frictional characteristics of the composites and coppe... Two Al2O3/Cu composites containing 0.24 wt.% Al2O3 and 0.60 wt.% Al2O3 separately are prepared by internal oxidation. Effects of sliding speed and pressure on the frictional characteristics of the composites and copper against brass are investigated and compared. The changes in morphology of the sliding surface and subsurface are examined with scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDS). The results show that the wear resistance of the Al2O3/Cu composites is superior to that of copper under the same conditions, Under a given electrical current, the wear rate of Al2O3/Cu composites decreases as the Al2O3-content increases, However, the wear rates of the Al2O3/Cu composites and copper increase as the sliding speed and pressure increase under dry sliding condition. The main wear mechanisms for Al2O3/Cu composites are of abrasion and adhesion; for copper, it is adhesion, although wear by oxidation and electrical erosion can also be observed as the speed and pressure rise. 展开更多
关键词 Al2o3/Cu composite internal oxidation friction and wear surface morphology current carder
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Preparation of α-Bi_2O_3 from bismuth powders through low-temperature oxidation 被引量:4
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作者 夏纪勇 唐谟堂 +2 位作者 陈萃 金胜明 陈永明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第9期2289-2294,共6页
α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 ... α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation. 展开更多
关键词 bismuth powder low-temperature oxidation α-Bi2o3 oxidation kinetics
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Effect of La_2O_3/Ce O_2 particle size on high-temperature oxidation resistance of electrodeposited Ni-La_2O_3/Ce O_2 composites 被引量:4
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作者 孟君晟 吉泽升 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3571-3577,共7页
Ni-La2O3/CeO2 composite films were prepared by electrodeposition from a nickel sulfate bath containing certain content of micrometer and nanometer La2O3/CeO2 particles. The effect of La2O3 or CeO2 particle size on the... Ni-La2O3/CeO2 composite films were prepared by electrodeposition from a nickel sulfate bath containing certain content of micrometer and nanometer La2O3/CeO2 particles. The effect of La2O3 or CeO2 particle size on the oxidation resistance of the electrodeposited Ni-La2O3/CeO2 composites in air at 1000 °C was studied. The results indicate that, compared with the electrodeposited Ni-film, Ni-La2O3/CeO2 composites exhibit a superior oxidation resistance due to the codeposited La2O3 or CeO2 particles blocking the outward diffusion of nickel. Moreover, compared with nanoparticles, La2O3 or CeO2 microparticles have stronger effect because La2O3 or CeO2 microparticles also act as a diffusion barrier layer at the onset of oxidation. 展开更多
关键词 Ni-based composite ELECTRoDEPoSITIoN high-temperature oxidation LA2o3 CEo2 reactive element effect oxidation mechanism
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Impedance spectroscopy study of high-temperature oxidation of Gd_2O_3-Yb_2O_3 codoped zirconia thermal barrier coatings 被引量:2
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作者 张丹华 郭洪波 宫声凯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期1061-1067,共7页
3Gd2O3-3Yb2O3-4Y2O3 (mole fraction, %) co-doped ZrO2 (GY-YSZ) thermal barrier coatings (TBCs) were produced by electron beam physical vapor deposition (EB-PVD). The oxidation behavior of GY-YSZ at 1 050 ℃ was... 3Gd2O3-3Yb2O3-4Y2O3 (mole fraction, %) co-doped ZrO2 (GY-YSZ) thermal barrier coatings (TBCs) were produced by electron beam physical vapor deposition (EB-PVD). The oxidation behavior of GY-YSZ at 1 050 ℃ was investigated using impedance spectroscopy (IS) combined with scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffractometry (XRD). Various electrical responses observed in the impedance spectra corresponding to GY-YSZ grains and grain boundaries were explained using circuit modeling. The change in the conduction mechanism of GY-YSZ was found to be related to the O^2- vacancy and lattice distortion due to the stabilizer diffusion during the oxidation. The results also suggested that the specific oxidation information about the GY-YSZ grains and grain boundaries should be acquired at a moderate measurement temperature, which was related to the resistance value in the impedance spectra. The resistance values of the GY-YSZ grains and grain boundaries should be measured at 200 ℃ and 300 ℃, respectively. 展开更多
关键词 rare earth oxide GD2o3 YB2o3 thermal barrier coatings (TBCs) oxidation impedance spectroscopy (IS)
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Preparation and oxidation resistance of B_2O_3-coated boron-modified carbon foams 被引量:1
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作者 王斌 李贺军 +1 位作者 张雨雷 王茜 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2123-2128,共6页
To improve the oxidation resistance of boron-modified carbon foams, the B2O3 coating was prepared on boron-modified carbon foams by low-cost slurry method. The microstructures and phase compositions of the coated carb... To improve the oxidation resistance of boron-modified carbon foams, the B2O3 coating was prepared on boron-modified carbon foams by low-cost slurry method. The microstructures and phase compositions of the coated carbon foams were characterized by scanning electron microscopy and X-ray diffraction, respectively. Oxidation resistances of uncoated and coated boron-modified carbon foams were investigated at 873 K in air. The results showed that as-received B2O3 coating could protect boron-modified carbon foams from oxidation at 873 K. B2O3-coated carbon foam doped with 7% B2O3 (mass fraction) (BO-7) had better oxidation resistance, exhibiting mass loss of 17.40% after oxidation at 873 K for 120 min. The melting glass layer formed on the surface of BO-7 could prevent oxygen from diffusing into boron-modified carbon foams substrate during oxidation to some extent. 展开更多
关键词 carbon foam B2o3 CoATING oxidation resistance
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Preparation of Al_2O_3/Au nano-laminated composite coatings and their oxidation resistance on stainless steel 被引量:1
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作者 高俊国 陆峰 +2 位作者 汤智慧 王长亮 何业东 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2491-2497,共7页
Al2O3/Au nano-laminated composite coatings were prepared by means of magnetron sputtering. The coating was compact and comprised of nano-laminated Al2O3 and Au layers. High temperature cyclic oxidation test was employ... Al2O3/Au nano-laminated composite coatings were prepared by means of magnetron sputtering. The coating was compact and comprised of nano-laminated Al2O3 and Au layers. High temperature cyclic oxidation test was employed to investigate the oxidation resistance of the composite coatings. The results revealed that the applied Al2O3/Au nano-laminated composite coatings improved the oxidation and spallation resistance of the stainless steel substrate significantly. The mechanism accounting for oxidation resistance was related with the suppression of inward oxygen diffusion and selective oxidation of Cr in the substrate. The mechanism accounting for spallation resistance was attributed to the relaxation of thermal stress by the nano-laminated structure. 展开更多
关键词 Al2o3/Au composite coatings magnetron sputtering oxidation resistance spallation resistance
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Effect of Calcination Temperature on Surface Oxygen Vacancies and Catalytic Performance Towards CO Oxidation of Co3O4 Nanoparticles Supported on SiO2 被引量:1
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作者 李金兵 姜志全 +1 位作者 王坤 黄伟新 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第1期103-109,I0004,共8页
Co3O4/SiO2 catalysts for CO oxidation were prepared by conventional incipient wetness impregnation followed by calcination at various temperatures. Their structures were char- acterized with X-ray diffraction (XRD),... Co3O4/SiO2 catalysts for CO oxidation were prepared by conventional incipient wetness impregnation followed by calcination at various temperatures. Their structures were char- acterized with X-ray diffraction (XRD), laser Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and X-ray absorption fine structure (XAFS) spectroscopy. Both XRD and Raman spectroscopy only detect the existence of Co3O4 crystallites in all catalysts. However, XPS results indicate that excess Co2+ ions are present on the surface of Co3O4 in Co3O4(200)/Si02 as compared with bulk Co3O4. Meanwhile, TPR results suggest the presence of surface oxygen vacancies on Co3O4 in Co3O4(200)/SiO2, and XAFS results demonstrate that Co3O4 in Co3O4(200)/SIO2 contains excess Co2+. Increasing calcination temperature results in oxidation of excess Co2+ and the decrease of the concentration of surface oxygen vacancies, consequently the for- mation of stoichiometric Co3O4 on supported catalysts. Among all Co3O4/SiO2 catalysts, Co3O4(200)/SiO2 exhibits the best catalytic performance towards CO oxidation, demonstrating that excess Co2+ and surface oxygen vacancies can enhance the catalytic activity of Co3O4 towards CO oxidation. These results nicely demonstrate the effect of calcination temperature on the structure and catalytic performance towards CO oxidation of silicasupported Co3O4 catalysts and highlight the important role of surface oxygen vacancies on Co3O4. 展开更多
关键词 Co3o4/8io2 catalyst Co oxidation Calcination temperature Surface oxygen vacancies
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Enhanced CO oxidation over potassium-promoted Pt/Al_2O_3 catalysts:Kinetic and infrared spectroscopic study 被引量:1
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作者 刘欢欢 贾爱平 +2 位作者 王瑜 罗孟飞 鲁继青 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期1976-1986,共11页
A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-co... A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents (51.6 k)/mol for 0.42K-2.0Pt/Al2O3 and 6:3.6 kJ/mol for 2.0Pt/Al2O3 ). The CO reaction orders were higher for the K-containing catalysts (about -0.2) than for the K-free ones (about -0.5), with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species. 展开更多
关键词 Co oxidation Potassium Kinetics Pt/Al2o3 catalyst Promoting effect
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Treatment of phenol wastewater by microwave-induced CIO_2-CuO_x/Al_2O_3 catalytic oxidation process 被引量:28
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作者 BI Xiao-yi WANG Peng JIANG Hong XU Huan-yan SHI Shu-jie HUANG Jun-li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第12期1510-1515,共6页
The catalyst of CUOx/Al2O3 was prepared by the dipping-sedimentation method using y-Al2O3 as a supporter. CuO and Cu2O were loaded on the surface of Al2O3, characterized by X-ray diffraction (XRD) and X-ray photoele... The catalyst of CUOx/Al2O3 was prepared by the dipping-sedimentation method using y-Al2O3 as a supporter. CuO and Cu2O were loaded on the surface of Al2O3, characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In the presence of CuOx/Al2O3, the microwave-induced chlorine dioxide (ClO2) catalytic oxidation process was conducted for the treatment of synthetic wastewater containing 100 mg/L phenol. The factors influencing phenol removal were investigated and the results showed that microwave-induced C102-CuOx/ml203 process could effectively degrade contaminants in a short reaction time with a low oxidant dosage, extensive pH range. Under a given condition (ClO2 concentration 80 mg/L, microwave power 50 W, contact time 5 latin, catalyst dosage 50 g/L, pH 9), phenol removal percentage approached 92.24%, corresponding to 79.13% of CODcr removal. The removal of phenol by microwave-induced ClO2-CuOx/Al2O3 catalytic oxidation process was a complicated non-homogeneous solid/water reaction, which fitted pseudo-first-order by kinetics. Compared with traditional ClO2 oxidation, ClO2 catalytic oxidation and microwave-induced ClO2 oxidation, microwave-induced ClO2 catalytic oxidation system could significantly enhance the degradation efficiency. It provides an effective technology for the removal of phenol wastewater. 展开更多
关键词 microwave-induced oxidation CLo2 Cuox/Al2o3 phenol wastewater
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Al_2O_3-H_2O纳米流体相变蓄冷特性研究 被引量:23
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作者 杨硕 朱冬生 +1 位作者 吴淑英 李华 《制冷学报》 CAS CSCD 北大核心 2010年第1期23-26,共4页
在水介质中悬浮少量的纳米氧化铝颗粒(粒径20nm),通过添加分散剂和超声波振荡,制备成均匀分散的Al2O3-H2O纳米流体。对水和Al2O3-H2O纳米流体的相变蓄冷特性进行了实验比较。结果表明,加入纳米Al2O3可降低水的过冷度,缩短结冰时间;在相... 在水介质中悬浮少量的纳米氧化铝颗粒(粒径20nm),通过添加分散剂和超声波振荡,制备成均匀分散的Al2O3-H2O纳米流体。对水和Al2O3-H2O纳米流体的相变蓄冷特性进行了实验比较。结果表明,加入纳米Al2O3可降低水的过冷度,缩短结冰时间;在相同的时间内,纳米流体的蓄冷量要大于纯水。 展开更多
关键词 工程热物理 Al2o3-h2o纳米流体 过冷度 相变蓄冷
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Leaching kinetics of low grade zinc oxide ore in NH_3-NH_4Cl-H_2O system 被引量:13
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作者 王瑞祥 唐谟堂 +4 位作者 杨声海 张文海 唐朝波 何静 杨建广 《Journal of Central South University of Technology》 2008年第5期679-683,共5页
The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching effic... The leaching kinetics of low grade zinc oxide ore in NH3-NH4Cl-H2O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH3-NH4Cl-H2O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 ℃ for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2-1, and the ratio (g/mL) of solid to liquid being 1-10. 展开更多
关键词 NH3-NH4Cl-h2o system low-grade zinc oxide ore LEACHING KINETICS
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Catalytic Partial Oxidation of Methane over Ni/CeO_2-ZrO_2-Al_2O_3 被引量:7
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作者 梅大江 陈耀强 +3 位作者 钟俊波 魏振玲 马迪 龚茂初 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第3期311-315,共5页
Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction(XRD),BET areas,H2 temperature-programmed reduction(H2-TPR),and X-ray photoelectron sp... Nickel catalysts supported on CeO2-ZrO2-CeO2,ZrO2-Al2O3 and Al2O3 were prepared and characterized by means of X-ray diffraction(XRD),BET areas,H2 temperature-programmed reduction(H2-TPR),and X-ray photoelectron spectroscopy(XPS).Through the test of catalytic partial oxidation of methane(CPOM),Ni/CeO2-ZrO2-Al2O3 displayed the highest activity,which resulted from its largest BET area and best NiO dispersion.Furthermore,Ni/CeO2-ZrO2-Al2O3 maintained a long-time stability in CPOM,which was attributed to its best coking resistance among all the prepared catalysts. 展开更多
关键词 Ni/Ceo2-Zro2-Al2o3 catalyst catalytic partial oxidation of methane carbon deposition rare earths
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Insight into catalytic properties of Co3O4-CeO2 binary oxides for propane total oxidation 被引量:6
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作者 Wenjun Zhu Xiao Chen +3 位作者 Jianhui Jin Xin Di Changhai Liang Zhongmin Liu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第4期679-690,共12页
A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of... A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere. 展开更多
关键词 PRoPANE Total oxidation Co3o4-Ceo2 In-suit DRIFTS Volatile organic compounds
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硅锌矿在(NH_4)_2SO_4-NH_3-H_2O体系中的浸出机理 被引量:11
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作者 刘智勇 刘志宏 +2 位作者 曹志阎 李启厚 杨天足 《中国有色金属学报》 EI CAS CSCD 北大核心 2011年第11期2929-2935,共7页
对硅锌矿在(NH4)2SO4-NH3-H2O体系中的浸出行为进行了系统研究,揭示浸出反应机理,阐明其难以浸出的内在原因。结果表明:硅锌矿浸出反应方程为Zn2SiO4(s)+(2i-4)NH3(aq)+4NH4+=2[Zn(NH3)i]2++SiO2(s)+2H2O(l),i=1~4。浸出中,硅锌矿中的... 对硅锌矿在(NH4)2SO4-NH3-H2O体系中的浸出行为进行了系统研究,揭示浸出反应机理,阐明其难以浸出的内在原因。结果表明:硅锌矿浸出反应方程为Zn2SiO4(s)+(2i-4)NH3(aq)+4NH4+=2[Zn(NH3)i]2++SiO2(s)+2H2O(l),i=1~4。浸出中,硅锌矿中的硅溶解进入溶液,再以无定形SiO2形态从溶液中析出。SiO2在(NH4)2SO4-NH3-H2O体系中的溶解度很低,仅略高于0.3 g/L,而其从溶液中的析出速度非常缓慢,是硅锌矿在该体系中难以浸出的主要原因。当液固质量比从5提高至500时,锌浸出率将从2.72%提高至84.15%。 展开更多
关键词 硅锌矿 (NH4)2So4-NH3-h2o体系 浸出 机理
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