The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own in...The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own increases the initial permeability (μi) slightly, but SnO2 with SiO2 and/or CaO decreases the values of μi. However, ferrites with SnO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that SnO2 (with or without SiO2 and/or CaO) doping increases the hysteresis loss slightly, but SnO2 doping alone reduces the eddy current loss significantly (～14%). The additions of SiO2 or CaO further decrease the eddy current loss, and by interaction of SnO2-CaO-SiO2, the eddy current loss is reduced by more than 20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.展开更多
Porous Cu-doped SnO<sub>2</sub> thin films were synthesized by the sol-gel dip-coating method for enhancing methanol sensing performance. The effect of Cu doping concentration on the SnO<sub>2</su...Porous Cu-doped SnO<sub>2</sub> thin films were synthesized by the sol-gel dip-coating method for enhancing methanol sensing performance. The effect of Cu doping concentration on the SnO<sub>2</sub> sensibility was investigated. XRD data confirm that the fabricated SnO<sub>2</sub> films are polycrystalline with tetragonal rutile crystal structure. AFM and SEM micrographs confirmed the roughness and the porosity of SnO<sub>2</sub> surface, respectively. UV-Vis spectrum shows that SnO<sub>2</sub> thin films exhibit high transmittance in the visible region ~95%. The band gap (3.80 - 3.92 eV) and the optical thickness (893 - 131 nm) of prepared films were calculated from transmittance data. The sensing results demonstrate that SnO<sub>2</sub> films have a high sensitivity and a fast response to methanol. In particular, 3% Cu-SnO<sub>2</sub> films have a higher sensitivity (98%), faster response (10-<sup>2</sup> s) and shorter recovery time (18 s) than other films.展开更多
The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray ana...The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray analysis （EDAX）, inductively coupled plasma （ICP）, atomic absorption spectroscopic （AAS） analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.展开更多
Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential fo...Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential for CO_(2)reduction reaction(CO_(2)-RR)due to their ability to operate at high temperatures,resulting in fast reaction kinetics and increased efficiency.Considering their main energy loss is still associated with the large overpotential at the fuel electrode,the development of the highly efficient and durable cathode for SOECs has been extensively searched after.Here,we propose an A-site doping strategy to enhance the properties of Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)(SFM),which improve its performance as a cathode in SOECs for CO_(2)-RR,demonstrating favorable activity and durability.The structural and physiochemical characterizations,together with DFT calculations,show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO_(2) adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide,resulting in enhanced CO_(2)electrocatalysis performance in SOECs.Specifically,a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ) (LSGM)electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm^(−2) at a cell potential of 1.6 V at 850°C with good operational stability up to 200 h.Bi-doped SFM thus represents a highly promising cathode for ceramic CO_(2)electrolyzers and could accelerate our transition towards a carbon-neutral society.展开更多
Thermoelectric properties of Li-doped Sr0.70Ba0.30Nb2O6-δ ceramics were investigated in the temperature range from 323 K to 1073 K. The electrical conductivity increases significantly after lithium interstitial dopin...Thermoelectric properties of Li-doped Sr0.70Ba0.30Nb2O6-δ ceramics were investigated in the temperature range from 323 K to 1073 K. The electrical conductivity increases significantly after lithium interstitial doping. However, both of the magnitudes of Seebeck coefficient and electrical conductivity vary non-monotonically but synchronously with the doping contents, indicating that doped lithium ions may not be fully ionized and oxygen vacancy may also contribute to carriers. The lattice thermal conductivity increases firstly and then decreases as the doping content increases, which is affected by competing factors.Thermoelectric performance is enhanced by lithium interstitial doping due to the increase of the power factor and the thermoelectric figure of merit reaches maximum value （0.21 at 1073 K） in the sample Sr0.70Ba0.30Li0.10Nb2O6.展开更多
文摘The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own increases the initial permeability (μi) slightly, but SnO2 with SiO2 and/or CaO decreases the values of μi. However, ferrites with SnO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that SnO2 (with or without SiO2 and/or CaO) doping increases the hysteresis loss slightly, but SnO2 doping alone reduces the eddy current loss significantly (～14%). The additions of SiO2 or CaO further decrease the eddy current loss, and by interaction of SnO2-CaO-SiO2, the eddy current loss is reduced by more than 20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.
文摘Porous Cu-doped SnO<sub>2</sub> thin films were synthesized by the sol-gel dip-coating method for enhancing methanol sensing performance. The effect of Cu doping concentration on the SnO<sub>2</sub> sensibility was investigated. XRD data confirm that the fabricated SnO<sub>2</sub> films are polycrystalline with tetragonal rutile crystal structure. AFM and SEM micrographs confirmed the roughness and the porosity of SnO<sub>2</sub> surface, respectively. UV-Vis spectrum shows that SnO<sub>2</sub> thin films exhibit high transmittance in the visible region ~95%. The band gap (3.80 - 3.92 eV) and the optical thickness (893 - 131 nm) of prepared films were calculated from transmittance data. The sensing results demonstrate that SnO<sub>2</sub> films have a high sensitivity and a fast response to methanol. In particular, 3% Cu-SnO<sub>2</sub> films have a higher sensitivity (98%), faster response (10-<sup>2</sup> s) and shorter recovery time (18 s) than other films.
文摘The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray analysis （EDAX）, inductively coupled plasma （ICP）, atomic absorption spectroscopic （AAS） analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.
基金financially supported by the State Key Laboratory of Clean Energy Utilization(Open Fund Project No.ZJUCEU2021001)Natural Science Foundation of Jiangsu Province(No.BK20221312).
文摘Electrochemical conversion of CO_(2)to CO is an economically feasible method for mitigating greenhouse gas emissions.Among various electrochemical approaches,solid oxide electrolysis cells(SOECs)show high potential for CO_(2)reduction reaction(CO_(2)-RR)due to their ability to operate at high temperatures,resulting in fast reaction kinetics and increased efficiency.Considering their main energy loss is still associated with the large overpotential at the fuel electrode,the development of the highly efficient and durable cathode for SOECs has been extensively searched after.Here,we propose an A-site doping strategy to enhance the properties of Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)(SFM),which improve its performance as a cathode in SOECs for CO_(2)-RR,demonstrating favorable activity and durability.The structural and physiochemical characterizations,together with DFT calculations,show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO_(2) adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide,resulting in enhanced CO_(2)electrocatalysis performance in SOECs.Specifically,a La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(0.2)O_(3−δ) (LSGM)electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm^(−2) at a cell potential of 1.6 V at 850°C with good operational stability up to 200 h.Bi-doped SFM thus represents a highly promising cathode for ceramic CO_(2)electrolyzers and could accelerate our transition towards a carbon-neutral society.
基金supported by the National Basic Research Program of China(Grant No.2013CB632506)the National Natural Science Foundation of China(Grant Nos.51202132,51231007,and 11374186)
文摘Thermoelectric properties of Li-doped Sr0.70Ba0.30Nb2O6-δ ceramics were investigated in the temperature range from 323 K to 1073 K. The electrical conductivity increases significantly after lithium interstitial doping. However, both of the magnitudes of Seebeck coefficient and electrical conductivity vary non-monotonically but synchronously with the doping contents, indicating that doped lithium ions may not be fully ionized and oxygen vacancy may also contribute to carriers. The lattice thermal conductivity increases firstly and then decreases as the doping content increases, which is affected by competing factors.Thermoelectric performance is enhanced by lithium interstitial doping due to the increase of the power factor and the thermoelectric figure of merit reaches maximum value （0.21 at 1073 K） in the sample Sr0.70Ba0.30Li0.10Nb2O6.
