实验表明,在氧化钒中掺杂不同的物质与不同的比例制作的邻界热敏电阻CTR(Critical Temperature Resister)样品的VO2相变点得到了提高,发生了偏移,这种偏移与掺杂成份与比例有一定的关系.根据样品对应的热谱图,从样品成份中VO2、Fe2O3、P...实验表明,在氧化钒中掺杂不同的物质与不同的比例制作的邻界热敏电阻CTR(Critical Temperature Resister)样品的VO2相变点得到了提高,发生了偏移,这种偏移与掺杂成份与比例有一定的关系.根据样品对应的热谱图,从样品成份中VO2、Fe2O3、P2O5微观结构分析各成份所起的作用.设计制作3种掺杂比例不同的样品,比较其不同组份相变点的偏移.此方案得出,在制作邻界热敏电阻CTR时各组份相互牵制相互影响的关系.VO2的相对量与相变点温度成正比关系;P2O5的相对量影响VO2微晶的稳定,也会影响Fe2O3的变价和电子的传导,从而影响VO2的相变;Fe2O3的量与VO2导体性能成正比关系,相对量大,相变点温度将降低.展开更多
A 60%Fe/Al_2O_3 catalyst was prepared by the co-precipitation method.It was reduced by H_2 to produce metallic Fe,which was then sulfided by CS_2 to Fe_(0.96) S and Fe_3S_4 or phosphided by triphenylphosphine(PPh3) in...A 60%Fe/Al_2O_3 catalyst was prepared by the co-precipitation method.It was reduced by H_2 to produce metallic Fe,which was then sulfided by CS_2 to Fe_(0.96) S and Fe_3S_4 or phosphided by triphenylphosphine(PPh3) in liquid phases to Fe2 P and Fe P.It was found that the iron sulfides(Fe0.96 S and Fe_3S_4) exhibited the low activity for the hydrodesulfurization(HDS) reactions.The HDS activity was also low on the Fe(metal)/Al_2O_3 and Fe_2 P/Al_2O_3 catalysts since they were converted into Fe0.96 S and Fe_3S_4 during the HDS reactions.In contrast,the FeP/Al_2O_3 was found to be stable and active for the HDS reactions.In particular,Fe P/Al_2O_3 possessed significantly smaller Fe P particles than Fe P/C,leading to the significant higher HDS activity of FeP/Al_2O_3 than Fe P/C.展开更多
In this study, Ni/YZrOcatalysts prepared with impregnation method and treated by dielectric barrier discharge plasma(DBD) in different atmospheres have been investigated for methane dry reforming. It is revealed by H-...In this study, Ni/YZrOcatalysts prepared with impregnation method and treated by dielectric barrier discharge plasma(DBD) in different atmospheres have been investigated for methane dry reforming. It is revealed by H-TPR that plasma treatment can enhance the interaction between Ni O/Ni particles and the YZrOpyrochlore support. Therefore, catalysts with smaller Ni O and Ni grains sizes, higher metallic Ni active surface areas can be achieved, as evidenced by XRD, TEM and Hadsorption-desorption measurements. As a consequence, the plasma-treated catalysts show significantly improved activity, stability and coke resistance, as testified by the TEM and TGA-DSC results. Plasma treatment in H/Ar gas mixture is found to be the best condition to prepare Ni/YZrO, which can be used to obtain a catalyst with the highest activity, stability and most potent coke resistance. It is believed that the smaller Ni grain size and higher metallic Ni active surface area induced by plasma treatment are the inherent reasons accounting for the promoted reaction performance of the Ni/YZrOpyrochlore catalysts.展开更多
To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO lo...To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations.In these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)surface.When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure.In contrast,Cu has negligible interactions with La at the A-sites.This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support.The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion activity.The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached.Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites.In summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer.展开更多
The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecul...The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.展开更多
Design of the catalyst for efficient water dissociation and hydrogen recombination is paramount in enhancement of the alkaline water electrolysis kinetics.Herein,we reported a delicate hierarchical(VO)_(2) P_(2)O_(7)-...Design of the catalyst for efficient water dissociation and hydrogen recombination is paramount in enhancement of the alkaline water electrolysis kinetics.Herein,we reported a delicate hierarchical(VO)_(2) P_(2)O_(7)-Ni_(2) P@NF(VPO-Ni_(2) P@NF)hybrid catalyst that operated efficiently in alkaline media.The VPO and Ni_(2) P respectively act as the water dissociation promoter and the hydrogen recombination center,which synergistically propel water adsorption/dissociation and H intermediates recombination.The resulting synergistic interfaces between VPO and Ni_(2) P are verified to afford the catalyst an outstanding performance for hydrogen evolution reaction in alkaline media with an overpotential of 154 mV at 10 mA cm^(-2),Tafel slope of 65 mV dec^(-1),and remarkable durability.Furthermore,the catalyst presents the potential for overall water splitting.This work may shed fresh light on the high-performance electrocatalyst design and the application of VPO on water electrolysis.展开更多
用电子陶瓷工艺制备了三种不同掺杂比例的临界热敏电阻CTR(Critical Temperature Resister),根据样品对应的热谱中的相变点,找出Fe2O3掺杂量与相变点的关系。从微观半导体理论分析晶粒体电特性,求解泊松方程,得出晶粒体中电势垒与受主杂...用电子陶瓷工艺制备了三种不同掺杂比例的临界热敏电阻CTR(Critical Temperature Resister),根据样品对应的热谱中的相变点,找出Fe2O3掺杂量与相变点的关系。从微观半导体理论分析晶粒体电特性,求解泊松方程,得出晶粒体中电势垒与受主杂质Fe2O3掺杂量的关系。结果表明:当x(Fe2O3)为10%～25%时,相变温度增加值?t和摩尔分数增加值(?x)2呈线性关系。展开更多
文摘实验表明,在氧化钒中掺杂不同的物质与不同的比例制作的邻界热敏电阻CTR(Critical Temperature Resister)样品的VO2相变点得到了提高,发生了偏移,这种偏移与掺杂成份与比例有一定的关系.根据样品对应的热谱图,从样品成份中VO2、Fe2O3、P2O5微观结构分析各成份所起的作用.设计制作3种掺杂比例不同的样品,比较其不同组份相变点的偏移.此方案得出,在制作邻界热敏电阻CTR时各组份相互牵制相互影响的关系.VO2的相对量与相变点温度成正比关系;P2O5的相对量影响VO2微晶的稳定,也会影响Fe2O3的变价和电子的传导,从而影响VO2的相变;Fe2O3的量与VO2导体性能成正比关系,相对量大,相变点温度将降低.
基金Financial supports from the NSFC-DFG (21761132006),NSFC (21773108)fundamental research funds for central universities are acknowledged
文摘A 60%Fe/Al_2O_3 catalyst was prepared by the co-precipitation method.It was reduced by H_2 to produce metallic Fe,which was then sulfided by CS_2 to Fe_(0.96) S and Fe_3S_4 or phosphided by triphenylphosphine(PPh3) in liquid phases to Fe2 P and Fe P.It was found that the iron sulfides(Fe0.96 S and Fe_3S_4) exhibited the low activity for the hydrodesulfurization(HDS) reactions.The HDS activity was also low on the Fe(metal)/Al_2O_3 and Fe_2 P/Al_2O_3 catalysts since they were converted into Fe0.96 S and Fe_3S_4 during the HDS reactions.In contrast,the FeP/Al_2O_3 was found to be stable and active for the HDS reactions.In particular,Fe P/Al_2O_3 possessed significantly smaller Fe P particles than Fe P/C,leading to the significant higher HDS activity of FeP/Al_2O_3 than Fe P/C.
基金supported by the National Natural Science Foundation of China (21567016, 21566022, 21263015)the Natural Science Foundation of Jiangxi Province (20151BBE50006, 20151BAB203024)the Education Department of Jiangxi Province (KJLD14005, GJJ150016)
文摘In this study, Ni/YZrOcatalysts prepared with impregnation method and treated by dielectric barrier discharge plasma(DBD) in different atmospheres have been investigated for methane dry reforming. It is revealed by H-TPR that plasma treatment can enhance the interaction between Ni O/Ni particles and the YZrOpyrochlore support. Therefore, catalysts with smaller Ni O and Ni grains sizes, higher metallic Ni active surface areas can be achieved, as evidenced by XRD, TEM and Hadsorption-desorption measurements. As a consequence, the plasma-treated catalysts show significantly improved activity, stability and coke resistance, as testified by the TEM and TGA-DSC results. Plasma treatment in H/Ar gas mixture is found to be the best condition to prepare Ni/YZrO, which can be used to obtain a catalyst with the highest activity, stability and most potent coke resistance. It is believed that the smaller Ni grain size and higher metallic Ni active surface area induced by plasma treatment are the inherent reasons accounting for the promoted reaction performance of the Ni/YZrOpyrochlore catalysts.
文摘To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations.In these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)surface.When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure.In contrast,Cu has negligible interactions with La at the A-sites.This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support.The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion activity.The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached.Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites.In summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer.
基金supported by the National Nature Science Foundation of China(No.20903054).
文摘The surface nature of fresh Mo2N/Al2O3, Mo2C/Al2O3 and/MoP/Al2O3 catalysts, which were synthesized directly in the IR cell to avoid passivation, were characterized by in situ IR spectroscopy with CO as a probe molecule. CO adsorbed on fresh catalysts showed characteristic IR bands at 2045 cm-1 for Mo2N/Al2O3 catalyst, 2054 cm-1 for MozC/Al2O3 catalyst and 2037 cm-1 for MoP/Al2O3 catalyst, respectively. A strong band at 2200 cm-1 for Mo2N/Al2O3 catalyst, which could be ascribed to NCO species formed when CO reacted upon surface active nitrogen atoms, and a weak band at 2196 cm-1 for Mo2C/Al2O3 catalyst, which could be attributed to CCO species, were also detected. CO adsorbed on fresh Mo2N/Al2O3 catalyst, Mo2C/Al2O3 catalyst and MoP/Al2O3 catalyst, showed strong molecular adsorption, just like noble metals. Our experimental results are bolstered by direct IR evidence demonstrating the similarity in surface electronic property between the fresh Mo2N/Al2O3, Mo2C/Al2O3 and MoP/Al2O3 catalysts and noble metals.
基金supported by the National Natural Science Foundation of China(No.51902232)。
文摘Design of the catalyst for efficient water dissociation and hydrogen recombination is paramount in enhancement of the alkaline water electrolysis kinetics.Herein,we reported a delicate hierarchical(VO)_(2) P_(2)O_(7)-Ni_(2) P@NF(VPO-Ni_(2) P@NF)hybrid catalyst that operated efficiently in alkaline media.The VPO and Ni_(2) P respectively act as the water dissociation promoter and the hydrogen recombination center,which synergistically propel water adsorption/dissociation and H intermediates recombination.The resulting synergistic interfaces between VPO and Ni_(2) P are verified to afford the catalyst an outstanding performance for hydrogen evolution reaction in alkaline media with an overpotential of 154 mV at 10 mA cm^(-2),Tafel slope of 65 mV dec^(-1),and remarkable durability.Furthermore,the catalyst presents the potential for overall water splitting.This work may shed fresh light on the high-performance electrocatalyst design and the application of VPO on water electrolysis.
文摘用电子陶瓷工艺制备了三种不同掺杂比例的临界热敏电阻CTR(Critical Temperature Resister),根据样品对应的热谱中的相变点,找出Fe2O3掺杂量与相变点的关系。从微观半导体理论分析晶粒体电特性,求解泊松方程,得出晶粒体中电势垒与受主杂质Fe2O3掺杂量的关系。结果表明:当x(Fe2O3)为10%～25%时,相变温度增加值?t和摩尔分数增加值(?x)2呈线性关系。
