Solid ceramic electrolyte materials (Bi_2O_3)_(0.75)(Y_2O_3)_(0.25) and(Bi_2O_3)_(0.65)(Gd_2O_3 )_(0.35)were synthesized.Their crystal structure, XPS spectra and the change of ionic conductivity versus temperature wer...Solid ceramic electrolyte materials (Bi_2O_3)_(0.75)(Y_2O_3)_(0.25) and(Bi_2O_3)_(0.65)(Gd_2O_3 )_(0.35)were synthesized.Their crystal structure, XPS spectra and the change of ionic conductivity versus temperature were measured.A Bi_2O_3-based rare earth solid electrolyte fuel cell with ZrO_2-Y_2O_3 protection film was made.展开更多
Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,a...Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.展开更多
The limited redox capability of photocatalysts often leads to harmful NO_(2) byproduct formation during photocatalytic NO oxidation.Herein,Bi_(4)Ti_(3)O_(12) nanosheets modified with plasmonic metallic bismuth and abu...The limited redox capability of photocatalysts often leads to harmful NO_(2) byproduct formation during photocatalytic NO oxidation.Herein,Bi_(4)Ti_(3)O_(12) nanosheets modified with plasmonic metallic bismuth and abundant oxygen vacancies were synthesized via an in-situ reduction method.The optimized catalyst(BTOR2,with a molar ratio of 40%NaBH_(4) to Bi_(4)Ti_(3)O_(12))achieved a maximum NO removal efficiency of 62.3%,significantly higher than pristine Bi_(4)Ti_(3)O_(12)(40.5%) while minimizing NO_(2) production.The results reveal that the synergistic effects of Bi’s plasmonic resonance and oxygen vacancies enhanced visible light absorption and charge separation.The density functional theory(DFT)analysis showed electrons can transfer from Bi_(4)Ti_(3)O_(12)to Bi,promoting O_(2)activation to·O_(2)^(-)radicals.In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)confirmed that light-induced H2O adsorption was strengthened,improving·OH radical generation.These radicals promoted the selective conversion of activated NO-to NO_(3)^(-),rather than NO_(2).This work provides valuable insights for advancing research into efficient photocatalysts for air pollution control.展开更多
The reaction behavior between CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags and La-bearing FeCrAl melt was quantitatively characterized,which was further compared with the reaction behavior of CaO–SiO_(2)-based slags.Bas...The reaction behavior between CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags and La-bearing FeCrAl melt was quantitatively characterized,which was further compared with the reaction behavior of CaO–SiO_(2)-based slags.Based on this,the new type of mold flux for La-bearing FeCrAl alloy continuous casting was designed and its basic properties were evaluated.The results showed that the order of reaction degree of fluxing agents in CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags is(Na_(2)O)>(B_(2)O_(3))>(Li_(2)O),and the percentages of mass change of fluxing agents were 85.8,54.29 and 42.35 wt.%,respectively.Moreover,the addition of(Li_(2)O)and(Na_(2)O)promoted the reaction between(CaO)and[Al],and the reaction degree of the former was weaker than that of the latter,which was due to the greater effect of(Na_(2)O)on the activity of(CaO)and(Al_(2)O_(3))than(Li_(2)O).Compared with the reactivity of CaO–SiO_(2)-based slags,the percentages of mass change of Al and La caused by slag–steel reaction decreased by 10.63–14.36 and 39.78–50.49 wt.%,respectively.The percentages of mass change of(Al_(2)O_(3)),(La_(2)O_(3))and(CaO)in slags highest increased by 17.71,17.98,and 7.81 wt.%,respectively.The reactivity of CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags was significantly weakened.Ultimately,the new type of mold flux was designed and the composition range was determined.The fundamental properties of new mold flux basically meet the theoretical requirements for La-bearing FeCrAl alloy continuous casting.展开更多
Al_(2)O_(3)-based eutectic ceramics are considered as promising candidates for ultra-high-temperature structural materials due to their exceptional thermal stability and mechanical properties.Nonetheless,several chall...Al_(2)O_(3)-based eutectic ceramics are considered as promising candidates for ultra-high-temperature structural materials due to their exceptional thermal stability and mechanical properties.Nonetheless,several challenges must be overcome before they can be widely used.This paper reviews in detail the tailoring of microstructure from the aspect of process parameters,the updated knowledge gained in microstructure(crystallographic orientation,high-resolution interfacial structures)and the latest means of optimizing eutectic microstructure(seed-induced method,introducing low-energy grain boundaries and high-entropy phase).Additionally,the paper explores future techniques for the fabrication of bulk ceramic materials and effective toughening approaches.This review highlights the achievements made especially in the last 15 years,current limitations in Al_(2)O_(3)-based eutectic ceramics,and offers comprehensive insights and strategic guidance for further mechanical breakthroughs.展开更多
In this study,S-scheme-based hydrothermal synthesis of Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)layered composites has been successfully reported.The photo-degradation of toxic dyes,viz.methyl orange(MO),and methylene blue(MB...In this study,S-scheme-based hydrothermal synthesis of Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)layered composites has been successfully reported.The photo-degradation of toxic dyes,viz.methyl orange(MO),and methylene blue(MB),has been used to examine nanocomposites with varying weight percent of Bi_(2)S_(3)for photocat-alytic activity in the visible range.Among candidates,Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)with a 10%loading of Bi_(2)S_(3)outperformed both pure and hybrid composites in photocatalytic activity.For MO degradation,the hybrid composite with 10%Bi_(2)S_(3)loading degrades 7.04 times higher than pristine CuBi_(2)O_(4)and Bi_(2)S_(3)samples,and for MB degradation,it degrades 4.96 times higher than pristine samples.High surface area,less re-combination rate of photogenerated charge carriers,photogenerated carriers faster separation,and high redox ability of Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)(10%)are all attributed to the improving photocatalytic perfor-mance.Even after ten cycles,the hybrid composite is chemically stable and reusable.Carbon nanotubes(CNTs)are a transfer bridge in layered structure for electrons because of their coordinated Fermi level between Ag-CuBi_(2)O_(4)and Bi_(2)S_(3).In addition,the scavenger and electron spin resonance(ESR)experiments verified that·O_(2)^(−),·OH,and h+were the important reactive species that successfully facilitated the pho-tocatalytic degradation process to degrade dyes.This study presents a straightforward and economical approach for obtaining a stable semiconductor-based photocatalytic system and a potential technique for future applications.展开更多
文摘Solid ceramic electrolyte materials (Bi_2O_3)_(0.75)(Y_2O_3)_(0.25) and(Bi_2O_3)_(0.65)(Gd_2O_3 )_(0.35)were synthesized.Their crystal structure, XPS spectra and the change of ionic conductivity versus temperature were measured.A Bi_2O_3-based rare earth solid electrolyte fuel cell with ZrO_2-Y_2O_3 protection film was made.
基金supported by the National Natural Science Foundation of China (No. 52374292)China Baowu Low Carbon Metallurgy Innovation Foundation, China (No. BWLCF202309)the Natural Science Foundation of Changsha City, China (No. KQ2208271)。
文摘Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.
基金supported by the Natural Science Foundation of Chongqing(Nos.CSTB2024NSCQ-MSX1278,CSTB2023NSCQ-MSX0006)Technology Innovation Project of Shapingba District,Chongqing(No.2024004)+2 种基金Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJZD-K202403102,KJQN202103110,KJQN202400512,KJQN202403107)National Natural Science Foundation of China(No.22406014)China Postdoctoral Science Foundation(No.2023MD744137).
文摘The limited redox capability of photocatalysts often leads to harmful NO_(2) byproduct formation during photocatalytic NO oxidation.Herein,Bi_(4)Ti_(3)O_(12) nanosheets modified with plasmonic metallic bismuth and abundant oxygen vacancies were synthesized via an in-situ reduction method.The optimized catalyst(BTOR2,with a molar ratio of 40%NaBH_(4) to Bi_(4)Ti_(3)O_(12))achieved a maximum NO removal efficiency of 62.3%,significantly higher than pristine Bi_(4)Ti_(3)O_(12)(40.5%) while minimizing NO_(2) production.The results reveal that the synergistic effects of Bi’s plasmonic resonance and oxygen vacancies enhanced visible light absorption and charge separation.The density functional theory(DFT)analysis showed electrons can transfer from Bi_(4)Ti_(3)O_(12)to Bi,promoting O_(2)activation to·O_(2)^(-)radicals.In-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)confirmed that light-induced H2O adsorption was strengthened,improving·OH radical generation.These radicals promoted the selective conversion of activated NO-to NO_(3)^(-),rather than NO_(2).This work provides valuable insights for advancing research into efficient photocatalysts for air pollution control.
基金supported by the National Natural Science Foundation of China(Grant Nos.52174321,52274339 and 52074186).
文摘The reaction behavior between CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags and La-bearing FeCrAl melt was quantitatively characterized,which was further compared with the reaction behavior of CaO–SiO_(2)-based slags.Based on this,the new type of mold flux for La-bearing FeCrAl alloy continuous casting was designed and its basic properties were evaluated.The results showed that the order of reaction degree of fluxing agents in CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags is(Na_(2)O)>(B_(2)O_(3))>(Li_(2)O),and the percentages of mass change of fluxing agents were 85.8,54.29 and 42.35 wt.%,respectively.Moreover,the addition of(Li_(2)O)and(Na_(2)O)promoted the reaction between(CaO)and[Al],and the reaction degree of the former was weaker than that of the latter,which was due to the greater effect of(Na_(2)O)on the activity of(CaO)and(Al_(2)O_(3))than(Li_(2)O).Compared with the reactivity of CaO–SiO_(2)-based slags,the percentages of mass change of Al and La caused by slag–steel reaction decreased by 10.63–14.36 and 39.78–50.49 wt.%,respectively.The percentages of mass change of(Al_(2)O_(3)),(La_(2)O_(3))and(CaO)in slags highest increased by 17.71,17.98,and 7.81 wt.%,respectively.The reactivity of CaO–Al_(2)O_(3)–La_(2)O_(3)-based slags was significantly weakened.Ultimately,the new type of mold flux was designed and the composition range was determined.The fundamental properties of new mold flux basically meet the theoretical requirements for La-bearing FeCrAl alloy continuous casting.
基金financially supported by the National Natural Science Foundation of China(No.52171046)National Natural Science Foundation of China-key programme(No.52234010)the Fundamental Research Funds for the Central Universities and Shaanxi Provincial Key Science and Technology Innovation Team(No.2023-CX-TD-14).
文摘Al_(2)O_(3)-based eutectic ceramics are considered as promising candidates for ultra-high-temperature structural materials due to their exceptional thermal stability and mechanical properties.Nonetheless,several challenges must be overcome before they can be widely used.This paper reviews in detail the tailoring of microstructure from the aspect of process parameters,the updated knowledge gained in microstructure(crystallographic orientation,high-resolution interfacial structures)and the latest means of optimizing eutectic microstructure(seed-induced method,introducing low-energy grain boundaries and high-entropy phase).Additionally,the paper explores future techniques for the fabrication of bulk ceramic materials and effective toughening approaches.This review highlights the achievements made especially in the last 15 years,current limitations in Al_(2)O_(3)-based eutectic ceramics,and offers comprehensive insights and strategic guidance for further mechanical breakthroughs.
基金the Researchers Supporting Project number(No.RSP2023R6),King Saud University,Riyadh,Saudi Arabia.
文摘In this study,S-scheme-based hydrothermal synthesis of Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)layered composites has been successfully reported.The photo-degradation of toxic dyes,viz.methyl orange(MO),and methylene blue(MB),has been used to examine nanocomposites with varying weight percent of Bi_(2)S_(3)for photocat-alytic activity in the visible range.Among candidates,Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)with a 10%loading of Bi_(2)S_(3)outperformed both pure and hybrid composites in photocatalytic activity.For MO degradation,the hybrid composite with 10%Bi_(2)S_(3)loading degrades 7.04 times higher than pristine CuBi_(2)O_(4)and Bi_(2)S_(3)samples,and for MB degradation,it degrades 4.96 times higher than pristine samples.High surface area,less re-combination rate of photogenerated charge carriers,photogenerated carriers faster separation,and high redox ability of Ag-CuBi_(2)O_(4)/CNTs/Bi_(2)S_(3)(10%)are all attributed to the improving photocatalytic perfor-mance.Even after ten cycles,the hybrid composite is chemically stable and reusable.Carbon nanotubes(CNTs)are a transfer bridge in layered structure for electrons because of their coordinated Fermi level between Ag-CuBi_(2)O_(4)and Bi_(2)S_(3).In addition,the scavenger and electron spin resonance(ESR)experiments verified that·O_(2)^(−),·OH,and h+were the important reactive species that successfully facilitated the pho-tocatalytic degradation process to degrade dyes.This study presents a straightforward and economical approach for obtaining a stable semiconductor-based photocatalytic system and a potential technique for future applications.
