RESUMO
The phase inversion tape casting has been widely used to fabricate open straight porous supports for solid oxide fuel cells (SOFCs), which can offer better gas transmission and minimize the concentration polarization. However, the overall weak strength of the macro-porous structure still limits the applications of these SOFCs. In this work, a novel SOFC supported by an ordered porous cathode membrane with a four-layer configuration containing a finger-like porous 3 mol% yttria- stabilized zirconia (3YSZ)-La0.8Sr0.2Co0.6Fe0.4O3-δ (LSCF) catalyst, porous 8 mol% yttria-stabilized zirconia (8YSZ)-LSCF catalyst, and dense 8YSZ porous 8YSZ-NiO catalyst is successfully prepared by the phase inversion tape casting, dip-coating, co-sintering, and impregnation process. The flexural strength of the open straight porous 3YSZ membrane is as high as 131.95 MPa, which meets the requirement for SOFCs. The cathode-supported single cell shows a peak power density of 540 mW cm-2 at 850 °C using H2 as the fuel. The degradation mechanism of the SOFC is investigated by the combination of microstructure characterization and distribution of relaxation times (DRT) analysis.
RESUMO
A farmland area in Zhaotong City was taken as the research objectï¼ and the method of point-to-point collaborative sampling was used to collect farmland soil and vegetables in Zhaotong and test the content of six heavy metalsï¼ namely Asï¼ Pbï¼ Cuï¼ Znï¼ Cdï¼ and Cr. The geo-accumulation index and potential ecological risk index were used to evaluate the heavy metal pollution of soil. The health risk model was used to evaluate the risk to the human body imposed by vegetables. The results showed that Cuï¼ Znï¼ Pbï¼ Cdï¼ and Cr pollution existed in the research area. Compared with the risk screening value of farmlandï¼ the over-standard rates were 34.35%ï¼ 6.87%ï¼ 2.29%ï¼ 80.15%ï¼ and 6.11%ï¼ respectivelyï¼ Pbï¼ Cdï¼ and Cr were found in vegetables. Compared with the pollutant limit in foodï¼ the over-standard rates were 6.87%ï¼ 15.27%ï¼ and 36.64%ï¼ respectively. According to the soil pollution evaluationï¼ Cd in the soil showed a strong ecological riskï¼ and other heavy metals in the soil showed a mild ecological risk. The human health risk evaluation model showed that both non-carcinogenic risk and carcinogenic risk were out of the acceptable range and had a greater influence on children. Correlation analysis showed that As in the soil had an antagonistic effect on Cu and Zn absorption by vegetablesï¼ whereas Cr in the soil could promote Cu and Zn absorption by vegetables.
Assuntos
Metais Pesados , Poluentes do Solo , Criança , Humanos , Solo , Fazendas , Verduras , Cádmio , Chumbo , Monitoramento Ambiental/métodos , Poluentes do Solo/análise , Metais Pesados/análise , Poluição Ambiental , Medição de Risco , ChinaRESUMO
Fe2TiO5/C photocatalysts were synthesized by a solid-state reaction method (Fe2TiO5/C(S)) and nonhydrolytic sol-gel (NHSG) method (Fe2TiO5/C(N)), where C was introduced by external carbon and in situ carbon sources, respectively. The Fe2TiO5/C(N) photocatalyst with in situ carbon has much better photocatalytic degradation efficiency than that of Fe2TiO5/C(S) synthesized by doping external carbon. The superiorities of in situ carbon were demonstrated by SEM, EDS, BET and photoelectrochemical analysis. Compared with Fe2TiO5/C(S) using external carbon as a carbon source, Fe2TiO5/C(N) with in situ carbon exhibits more uniform elemental distribution, much larger surface area, higher photocurrent density and lower resistivity of interfacial charge transfer. The results show that the introduction of in situ carbon via the NHSG method more easily promotes the separation of photogenerated electron-hole pairs, owing to the uniformity of the carbon element, thereby improving the photocatalytic activity of the photocatalyst.