The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to com...The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to comply with future ultra-low emission regulations.This paper studies a new type of Ce/La modified Cs-V non-noble metal CDPF catalyst.Three test catalysts(Cs-V,Cs-V-5%Ce,and Cs-V-5%La)were formulated to explore the physical properties,activity,and sulfur resistance through XRD,SEM,XPS,and TPO tests.And TGA tests with different catalyst-to-soot mass ratios were designed to analyze the reaction kinetics.The results show that the soot oxidation process is divided into three stages:slow oxidation,rapid oxidation,and soot burnout.SEM and XRD results show that,compared with Ce doping,La-doped catalysts have less damage to the microstructure of the first active component,Cs_(2)V_(4)O_(11).XPS results show that the introduction of Ce and La is beneficial to the formation of oxygen vacancies and lattice distortion,increasing the proportion of active oxygen species,thereby improving the soot oxidation activity,among which La-doped active oxygen species have the highest proportion(94%).And the Cs-V-5%La catalyst has the best effect on improving the soot conversion of the three stages.The fresh state has the best low-temperature activity index,the lowest characteristic temperature(T_(50) of 374℃)and activation energy(115.01 kJ/mol),and excellent sulfur resistance.The soot conversion and oxidation speed of the three stages decreases,duration lengthens,and activation energy increases by more than 100 kJ/mol as catalyst-to-soot mass ratios decrease.展开更多
采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其...采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其他副产物生成情况考察比较了空管放电、协同催化剂放电时催化降解甲苯性能,并对催化剂进行了BET、SEM、H2-TPR和ICP-OES表征研究。结果表明:稀土助剂的加入有助于提高甲苯去除率及降低程度,且La催化性能优于Ce.,当外加电压22 k V、气量6 L·min-1、甲苯初始浓度600 mg·m-3时,Mn-La/γ-Al_2O_3催化剂对甲苯去除率达到72.74%。H2-TPR结果表明,稀土助剂的加入提高了催化剂低温活性及储氧能力,添加La的效果优于Ce。催化剂有助于抑制副产物O_3生成,提高CO_2和COx选择性。展开更多
The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the a...The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-（Ce/La） phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.展开更多
The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current study.Compared with single Ca or...The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current study.Compared with single Ca or Ce/La addition,the Ca-Ce/La cooperative microalloying results in an outstanding grain refinement,because the fine secondary phase particles effectively hinder the recrystallized grain growth.The coarse Ca2Mg6Zn3 phases promote the formation of Ca3(PO4)2 or hydroxyapatite particles during the immersion process and accelerate the dissolution of the corrosion product film,which destroys its integrity and results in the deterioration of anti-corrosive performance.The Ce/La elements can be dispersed within the conventional Mg7Zn3 phases,which reduce the internal galvanic corrosion between Mg matrix and the secondary phases,leading to an obvious improvement of corrosion resistance.Therefore,the Ca-Ce/La cooperative microalloying achieves a homogenous fine-grained microstructure and improves the protective ability of surface film,which will pave a new avenue for the design of biomedical Mg alloys in the coming future.展开更多
基金supported by the National Natural Science Foundation of China(No.52206167)the Science and Technology Talents and Platform Program(Academician ExpertWorkstation)(No.202305AF150109)+1 种基金Shanghai Sailing Program(No.21YF1448900)the Introduced and co-builded high-level research and development institutions of Jiangxi Province(No.20212CCH45004).
文摘The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to comply with future ultra-low emission regulations.This paper studies a new type of Ce/La modified Cs-V non-noble metal CDPF catalyst.Three test catalysts(Cs-V,Cs-V-5%Ce,and Cs-V-5%La)were formulated to explore the physical properties,activity,and sulfur resistance through XRD,SEM,XPS,and TPO tests.And TGA tests with different catalyst-to-soot mass ratios were designed to analyze the reaction kinetics.The results show that the soot oxidation process is divided into three stages:slow oxidation,rapid oxidation,and soot burnout.SEM and XRD results show that,compared with Ce doping,La-doped catalysts have less damage to the microstructure of the first active component,Cs_(2)V_(4)O_(11).XPS results show that the introduction of Ce and La is beneficial to the formation of oxygen vacancies and lattice distortion,increasing the proportion of active oxygen species,thereby improving the soot oxidation activity,among which La-doped active oxygen species have the highest proportion(94%).And the Cs-V-5%La catalyst has the best effect on improving the soot conversion of the three stages.The fresh state has the best low-temperature activity index,the lowest characteristic temperature(T_(50) of 374℃)and activation energy(115.01 kJ/mol),and excellent sulfur resistance.The soot conversion and oxidation speed of the three stages decreases,duration lengthens,and activation energy increases by more than 100 kJ/mol as catalyst-to-soot mass ratios decrease.
文摘采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其他副产物生成情况考察比较了空管放电、协同催化剂放电时催化降解甲苯性能,并对催化剂进行了BET、SEM、H2-TPR和ICP-OES表征研究。结果表明:稀土助剂的加入有助于提高甲苯去除率及降低程度,且La催化性能优于Ce.,当外加电压22 k V、气量6 L·min-1、甲苯初始浓度600 mg·m-3时,Mn-La/γ-Al_2O_3催化剂对甲苯去除率达到72.74%。H2-TPR结果表明,稀土助剂的加入提高了催化剂低温活性及储氧能力,添加La的效果优于Ce。催化剂有助于抑制副产物O_3生成,提高CO_2和COx选择性。
基金supported by the National Natural Science Foundation of China(51401200)Natural Science Foundation of Jilin Province(20140520099JH)+4 种基金National Science & Technology Pillar Program(2012BAE01B04)Chinese Academy of Sciences of Western Action Plan Project(KZCX2-XB3-06)the National Natural Science Foundation of China Major Project(91122030)National High Technology Research and Development Program of China(2011AA03A407)National Natural Science Foundation for Creative Research Group(20921002)
文摘The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca（wt.%） alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-（Ce/La） phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.
基金the National Natural Science Foundation(Grant nos.5177117&51671152 and 51874225)the Key Research and Development Program of Shanxi Province(Grant nos.2020KWZ-007 and 2018ZDXMGY-149)the Youth Innovation Team of Shanxi Universities and the Natural Science Foundation of Jilin Province(Grant no.20180414016GH).
文摘The influences of Ca and Ce/La microalloying on the microstructure evolution and bio-corrosion resistances of extruded Mg-Zn alloys have been systematically investigated in the current study.Compared with single Ca or Ce/La addition,the Ca-Ce/La cooperative microalloying results in an outstanding grain refinement,because the fine secondary phase particles effectively hinder the recrystallized grain growth.The coarse Ca2Mg6Zn3 phases promote the formation of Ca3(PO4)2 or hydroxyapatite particles during the immersion process and accelerate the dissolution of the corrosion product film,which destroys its integrity and results in the deterioration of anti-corrosive performance.The Ce/La elements can be dispersed within the conventional Mg7Zn3 phases,which reduce the internal galvanic corrosion between Mg matrix and the secondary phases,leading to an obvious improvement of corrosion resistance.Therefore,the Ca-Ce/La cooperative microalloying achieves a homogenous fine-grained microstructure and improves the protective ability of surface film,which will pave a new avenue for the design of biomedical Mg alloys in the coming future.
