Three kinds of Ce-based catalysts(CePO_(4),CeVO_(4),Ce_(2)(SO_(4))_(3))were synthesized and used for the selective catalytic reduction(SCR)of NO by NH_(3).NH_(3)-SCR performances were conducted in the temperature rang...Three kinds of Ce-based catalysts(CePO_(4),CeVO_(4),Ce_(2)(SO_(4))_(3))were synthesized and used for the selective catalytic reduction(SCR)of NO by NH_(3).NH_(3)-SCR performances were conducted in the temperature range of 80 to 400°C.The catalytic efficiencies of the three catalysts are as follow:CePO_(4)>CeVO_(4)>Ce_(2)(SO_(4))_(3),which is in agreement with their abilities of NH_(3)adsorption capacities.The highest NO conversion rate of CePO_(4)could reach about 95%,and the catalyst had more than 90%NO conversion rate between 260 and 320°C.The effect of PO_(4)^(3–),VO_(4)^(3–)and SO_(4)^(2–)on NH_(3)-SCR performances of Ce-based catalysts was systematically investigated by the X-ray photoelectron spectroscopy analysis,NH_(3)temperature programmed desorption,H2 temperature programmed reduction and field emission scanning electron microscopy tests.The key factors that can enhance the SCR are the existence of Ce4+,large NH_(3)adsorption capacity,high and early H2 consumptions,and suitable microstructures for gas adsorption.Finally,CePO_(4)and CeVO_(4)catalysts also exhibited relatively strong tolerance of SO2,and the upward trend about 8%was detected due to the sulfation enhancement by SO2 for Ce_(2)(SO_(4))3.展开更多
The pristine CeVO_(4) and CeVO_(4)/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffraction results,the formation of tetragonal CeVO_(4) ...The pristine CeVO_(4) and CeVO_(4)/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffraction results,the formation of tetragonal CeVO_(4) with an additional minor phase of V_(2)O_(5) was identified.When investigated as an anode material for lithium(Li)-ion batteries,the CeVO_(4)/CNT hybrid composite nanostructure(HCNS) electrode demonstrated improved Li storage performance over the pristine CeVO_(4).The Li insertion/de-insertion electrochemical reaction with the CeVO_(4) was analyzed on the basis of cyclic voltammetry study.The cyclic voltammetry analysis revealed that the three-step reduction of V^(5+) to V^(3+), V^(3+) to V^(2+), and V^(2+) to V+ processes is involved and among them,only V^(5+) to V^(3+) is reversible during the Li-ion insertion into CeVO_(4).The CeVO_(4)/CNT HCNS electrode exhibited a discharge capacity as high as 443 mA h g^(-1)(capacity retention of 96.3%) over 200 cycles at 100 mA g^(-1), whereas the pristine CeVO_(4) is limited to 138 mA h g^(-1)(capacity retention of 48%).Even at a high current density of 500 mA g^(-1), the CeVO_(4)/CNT HCNS electrode delivered an excellent reversible capacity of 586.82 mA h g^(-1) after 1200 cycles.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.52102367)And the tests of XRD and XPS were supported by Research and Test Center of Materials,Wuhan University of TechnologyDRIFTS,TPD and TPR tests were supported by State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology.
文摘Three kinds of Ce-based catalysts(CePO_(4),CeVO_(4),Ce_(2)(SO_(4))_(3))were synthesized and used for the selective catalytic reduction(SCR)of NO by NH_(3).NH_(3)-SCR performances were conducted in the temperature range of 80 to 400°C.The catalytic efficiencies of the three catalysts are as follow:CePO_(4)>CeVO_(4)>Ce_(2)(SO_(4))_(3),which is in agreement with their abilities of NH_(3)adsorption capacities.The highest NO conversion rate of CePO_(4)could reach about 95%,and the catalyst had more than 90%NO conversion rate between 260 and 320°C.The effect of PO_(4)^(3–),VO_(4)^(3–)and SO_(4)^(2–)on NH_(3)-SCR performances of Ce-based catalysts was systematically investigated by the X-ray photoelectron spectroscopy analysis,NH_(3)temperature programmed desorption,H2 temperature programmed reduction and field emission scanning electron microscopy tests.The key factors that can enhance the SCR are the existence of Ce4+,large NH_(3)adsorption capacity,high and early H2 consumptions,and suitable microstructures for gas adsorption.Finally,CePO_(4)and CeVO_(4)catalysts also exhibited relatively strong tolerance of SO2,and the upward trend about 8%was detected due to the sulfation enhancement by SO2 for Ce_(2)(SO_(4))3.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIP)(No.2018R1A6A1A03025708 and No.2020R1A2B5B01002318)。
文摘The pristine CeVO_(4) and CeVO_(4)/CNT hybrid composite nanostructured samples were facilely synthesized using a simple silicone oil-bath method.From the X-ray diffraction results,the formation of tetragonal CeVO_(4) with an additional minor phase of V_(2)O_(5) was identified.When investigated as an anode material for lithium(Li)-ion batteries,the CeVO_(4)/CNT hybrid composite nanostructure(HCNS) electrode demonstrated improved Li storage performance over the pristine CeVO_(4).The Li insertion/de-insertion electrochemical reaction with the CeVO_(4) was analyzed on the basis of cyclic voltammetry study.The cyclic voltammetry analysis revealed that the three-step reduction of V^(5+) to V^(3+), V^(3+) to V^(2+), and V^(2+) to V+ processes is involved and among them,only V^(5+) to V^(3+) is reversible during the Li-ion insertion into CeVO_(4).The CeVO_(4)/CNT HCNS electrode exhibited a discharge capacity as high as 443 mA h g^(-1)(capacity retention of 96.3%) over 200 cycles at 100 mA g^(-1), whereas the pristine CeVO_(4) is limited to 138 mA h g^(-1)(capacity retention of 48%).Even at a high current density of 500 mA g^(-1), the CeVO_(4)/CNT HCNS electrode delivered an excellent reversible capacity of 586.82 mA h g^(-1) after 1200 cycles.
