Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we ...Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we successfully synthesized assembled hierarchical Bi2 WO6 which consists of ultrathin nanosheets with crystalline-amorphous composite phase by a one-step hydrothermal method. X-ray diffraction(XRD), X-ray photoemission spectroscopy(XPS), field-emission scanning electron microscopy(FESEM),and high-resolution transmission electron microscopy(HRTEM) techniques were employed to characterize its composition, morphology, and microstructure. By taking advantage of its unique microstructure,phase composition, and large surface area, we show that the resulting Bi2 WO6 is capable of detecting ethanol gas with quick response(7 s) and recovery dynamic(14 s), extremely high sensitivity(Ra/Rg= 60.8@50 ppm ethanol) and selectivity. Additionally, it has excellent reproducibility and long-term stability(more than 50 d). The Bi2 WO6 outperform the existing Bi2 WO6-based and most of the other state-of-the-art sensing platforms. We not only provided one new member to the field of gas sensor,but also offered several strategies to reconstruct nanomaterials.展开更多
为了提高Mg基非晶合金的塑性,在非晶基体中引入长周期(Long Period Order,LPO)结构晶态相,研究了Y/Zn含量对LPO结构形成的影响.采用铜模铸造制备了Mg77Ni12Zn9-xY2+x(x=0,2,4,6)非晶合金复合材料.采用扫描电镜(SEM)、高分辨透射电子显微...为了提高Mg基非晶合金的塑性,在非晶基体中引入长周期(Long Period Order,LPO)结构晶态相,研究了Y/Zn含量对LPO结构形成的影响.采用铜模铸造制备了Mg77Ni12Zn9-xY2+x(x=0,2,4,6)非晶合金复合材料.采用扫描电镜(SEM)、高分辨透射电子显微镜(HRTEM)、x-射线衍射仪(XRD)、能谱分析(EDX)等实验方法,对复合材料的组织、相组成和成分进行了研究.实验结果表明:形成具有14H类型LPO结构的最小Y/Zn值为0.57;形成均匀分布LPO相的Y/Zn比值为1.2,其中Y和Zn原子固溶在LPO结构中的比例略大于1.与Cu元素相比,Ni元素的存在使LPO结构类型由6H变为14H.通过各组成相在凝固过程中形核与长大过程,阐述了临界合金成分中LPO结构的形成过程及其热动力学机制.展开更多
Li-and Mn-rich(LMR)cathode materials have received tremendous attention due to the highly reversible specific capacity(>250 m Ah·g^(-1)).In the analysis of its crystal structure,the two-phase composite model g...Li-and Mn-rich(LMR)cathode materials have received tremendous attention due to the highly reversible specific capacity(>250 m Ah·g^(-1)).In the analysis of its crystal structure,the two-phase composite model gains increasing acceptance,and the phase transition behaviors in LMR cathode materials have been extensively studied.Herein,the structure controversy of LMR cathode materials,and the mechanisms of phase transition are summarized.Particularly,the causes of initiating or accelerating the phase transition of LMR cathode materials have been summarized into three main driving forces,i.e.,the electrochemical driving force,the component driving force and the thermodynamic driving force.Additionally,the applications of phase transition behavior in improving the electrochemical performance of LMR cathode materials,including the construction of spinel surface coating and spinel/layered hetero-structure are discussed.展开更多
4 mol.% Y203 stabilized ZrO2 （YSZ） doped with various quantifies of Gd203 （G-YSZ） ceramic comings were synthesized by electrophoretic deposition method, and followed by vacuum sintering and isothermally annealing ...4 mol.% Y203 stabilized ZrO2 （YSZ） doped with various quantifies of Gd203 （G-YSZ） ceramic comings were synthesized by electrophoretic deposition method, and followed by vacuum sintering and isothermally annealing at 1000 ℃ for different durations. X-ray diffraction （XRD） was used to investigate their phase composition. Scanning electron microscopy （SEM） was employed to examine their microstructure, while energy dispersive X-ray spectrometer （EDS） was used to assess composition of the composite coatings. The results indicated that YSZ coating was composed of tetragonal and monoclinic phase after vacuum sintefing at 1000 ~C for 2 h under vacuum （〈103 Pa）. G-YSZ composite coatings were composed of tetmgonal, monoclinic phase and a small amount of Gd2Zr207 phase after vacuum sintering at 1000 ℃ for 2 h, whereas the content ofmonoclinic phase in G-YSZ composite coatings in- creased with increasing Gd203 concentration. It was found that G-YSZ composite coatings were composed of tetragonal ZrO2 phase, monoclinic ZrO2 phase and cubic phase, whereas Gd2Zr207 phase disappeared, after G-YSZ composite coatings were isothermally annealed at 1000 ℃ in air for 100 h. A detailed description of the results and their discussion was presented in the paper.展开更多
基金supported by the National Key R&D Program of China (2017YFA0208300 and 2017YFA0700104)the National Natural Science Foundation of China (61671284, U1704255, and 21671180)the support of the Shanghai Municipal Education Commission (Peak Discipline Construction Program)
文摘Bismuth tungstate(Bi2 WO6) has many intriguing properties and has been the focus of studies in a variety of fields, especially photocatalysis. However, its application in gas-sensing has been seldom reported.Here, we successfully synthesized assembled hierarchical Bi2 WO6 which consists of ultrathin nanosheets with crystalline-amorphous composite phase by a one-step hydrothermal method. X-ray diffraction(XRD), X-ray photoemission spectroscopy(XPS), field-emission scanning electron microscopy(FESEM),and high-resolution transmission electron microscopy(HRTEM) techniques were employed to characterize its composition, morphology, and microstructure. By taking advantage of its unique microstructure,phase composition, and large surface area, we show that the resulting Bi2 WO6 is capable of detecting ethanol gas with quick response(7 s) and recovery dynamic(14 s), extremely high sensitivity(Ra/Rg= 60.8@50 ppm ethanol) and selectivity. Additionally, it has excellent reproducibility and long-term stability(more than 50 d). The Bi2 WO6 outperform the existing Bi2 WO6-based and most of the other state-of-the-art sensing platforms. We not only provided one new member to the field of gas sensor,but also offered several strategies to reconstruct nanomaterials.
文摘为了提高Mg基非晶合金的塑性,在非晶基体中引入长周期(Long Period Order,LPO)结构晶态相,研究了Y/Zn含量对LPO结构形成的影响.采用铜模铸造制备了Mg77Ni12Zn9-xY2+x(x=0,2,4,6)非晶合金复合材料.采用扫描电镜(SEM)、高分辨透射电子显微镜(HRTEM)、x-射线衍射仪(XRD)、能谱分析(EDX)等实验方法,对复合材料的组织、相组成和成分进行了研究.实验结果表明:形成具有14H类型LPO结构的最小Y/Zn值为0.57;形成均匀分布LPO相的Y/Zn比值为1.2,其中Y和Zn原子固溶在LPO结构中的比例略大于1.与Cu元素相比,Ni元素的存在使LPO结构类型由6H变为14H.通过各组成相在凝固过程中形核与长大过程,阐述了临界合金成分中LPO结构的形成过程及其热动力学机制.
基金the Natural Science Foundation of Fujian Province of China(Nos.2019J06003 and 2020J05014)the National Natural Science Foundation of China(Nos.51931006 and 51871188)+4 种基金the National Key R&D Program of China(No.2016YFA0202602)Guangdong Basic and Applied Basic Research Foundation(Nos.2021A1515010139 and 2019A1515011070)the Science and Technology Planning Projects of Fujian Province,China(No.2020H0005)the Fundamental Research Funds for the Central Universities of China(Nos.20720200068 and 20720190013)the“Double-First Class”Foundation of Materials Intelligent Manufacturing Discipline of Xiamen University。
文摘Li-and Mn-rich(LMR)cathode materials have received tremendous attention due to the highly reversible specific capacity(>250 m Ah·g^(-1)).In the analysis of its crystal structure,the two-phase composite model gains increasing acceptance,and the phase transition behaviors in LMR cathode materials have been extensively studied.Herein,the structure controversy of LMR cathode materials,and the mechanisms of phase transition are summarized.Particularly,the causes of initiating or accelerating the phase transition of LMR cathode materials have been summarized into three main driving forces,i.e.,the electrochemical driving force,the component driving force and the thermodynamic driving force.Additionally,the applications of phase transition behavior in improving the electrochemical performance of LMR cathode materials,including the construction of spinel surface coating and spinel/layered hetero-structure are discussed.
基金Project supported by Shanghai Municipal Developing Foundation of Science and Technology (0852nm01400)National Training Programs of Innovation for Undergraduates (201210856022)Science and Technology Key Fund Project of Shanghai University of Engi-neering Science (2011XZ07) for financial support
文摘4 mol.% Y203 stabilized ZrO2 （YSZ） doped with various quantifies of Gd203 （G-YSZ） ceramic comings were synthesized by electrophoretic deposition method, and followed by vacuum sintering and isothermally annealing at 1000 ℃ for different durations. X-ray diffraction （XRD） was used to investigate their phase composition. Scanning electron microscopy （SEM） was employed to examine their microstructure, while energy dispersive X-ray spectrometer （EDS） was used to assess composition of the composite coatings. The results indicated that YSZ coating was composed of tetragonal and monoclinic phase after vacuum sintefing at 1000 ~C for 2 h under vacuum （〈103 Pa）. G-YSZ composite coatings were composed of tetmgonal, monoclinic phase and a small amount of Gd2Zr207 phase after vacuum sintering at 1000 ℃ for 2 h, whereas the content ofmonoclinic phase in G-YSZ composite coatings in- creased with increasing Gd203 concentration. It was found that G-YSZ composite coatings were composed of tetragonal ZrO2 phase, monoclinic ZrO2 phase and cubic phase, whereas Gd2Zr207 phase disappeared, after G-YSZ composite coatings were isothermally annealed at 1000 ℃ in air for 100 h. A detailed description of the results and their discussion was presented in the paper.
