The Experts below are selected from a list of 5208 Experts worldwide ranked by ideXlab platform
Zongping Shao - One of the best experts on this subject based on the ideXlab platform.
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Nonstoichiometric perovskite for enhanced catalytic oxidation through excess A-Site Cation
Chemical Engineering Science, 2020Co-Authors: Ximu Li, Wei Zhou, Mengran Li, Xue Ma, Jie Miao, Shaobin Wang, Zongping ShaoAbstract:Abstract Perovskite oxide has been emerging as one of the efficient heterogeneous catalysts for advanced oxidation of organic contaminants in wastewater because of their structural integrity and compositional tunability. Herein, we report a new perovskite oxide, La1.15MnO3+δ with excess La, for a lowered average oxidation state of Mn Cations and abundant oxygen vacancies, which can be active Sites for peroxymonosulfate (PMS) activation. The La1.15MnO3+δ did exhibit improving catalytic performance as compared to LaMnO3+δ for the degradation of Rhodamine B by activating PMS. Besides, it also demonstrated high tolerance to variant water environments such as temperature, pH and impurity anions. A major non-radical activation mechanism dominated by 1O2 was further confirmed in La1.15MnO3+δ/PMS system, accompanied by a minor radical pathway. This work provides a new effective strategy to advance catalytic PMS oxidation processes by tailoring the oxidation state of B-Site metals and defects of perovskite oxide through manipulating A-Site Cation stoichiometry.
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Boosting the Activity of BaCo0.4Fe0.4Zr0.1Y0.1O3−δ Perovskite for Oxygen Reduction Reactions at Low‐to‐Intermediate Temperatures through Tuning B‐Site Cation Deficiency
Advanced Energy Materials, 2019Co-Authors: Xu Kuai, Wei Zhou, Guangming Yang, Yubo Chen, Yufei Song, Wei Wang, Zongping ShaoAbstract:Doped perovskite oxides with the general formula of AA′ BB′ O have been extensively exploited as the cathode materials of solid oxide fuel cells (SOFCs), but the performance at low-to-medium temperatures still needs improvement. BaCoFeZrYO (BCFZY) has been recently reported to show promising oxygen reduction reaction (ORR) activity under SOFCs' operating conditions. Here, it is reported that the activity of BCFZY can be further boosted via introducing a slight B-Site Cation deficiency into the oxide lattice, and such an improvement is assigned to an increase in oxygen mobility that brings enhancement in both surface exchange and bulk diffusion kinetics. Specifically, materials with the nominal composition of Ba(CoFeZrY)O and Ba(CoFeZrY)O show significantly improved activity for ORR at reduced temperatures with the area specific resistances of 0.011 and 0.024 Ω cm at 600 °C, as a comparison of 0.042 Ω cm for the Cation stoichiometric BCFZY. Excessive B-Site deficiencies, however, lead to the formation of impurity phases, which cause a block for charge transfer and, consequently, a reduction in electrode performance. Introducing a B-Site Cation deficiency is a promising way to optimize the activity of perovskite oxides for ORR at reduced temperatures, but the degree of deficiency shall be carefully tuned.
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b Site Cation ordered double perovskite oxide as an outstanding electrode material for supercapacitive energy storage based on the anion intercalation mechanism
ACS Applied Materials & Interfaces, 2018Co-Authors: Zhenye Xu, Wei Zhou, Moses O Tade, Zongping ShaoAbstract:Perovskite oxides are highly promising electrodes for oxygen-ion-intercalation-type supercapacitors owing to their high oxygen vacancy concentration, oxygen diffusion rate, and tap density. Based on the anion intercalation mechanism, the capacitance is contributed by surface redox reactions and oxygen ion intercalation in the bulk materials. A high concentration of oxygen vacancies is needed because it is the main charge carrier. In this study, we propose a B-Site Cation-ordered Ba2Bi0.1Sc0.2Co1.7O6−δ as an electrode material with an extremely high oxygen vacancy concentration and oxygen diffusion rate. A maximum capacitance of 1050 F g–1 was achieved, and a high capacitance of 780 F g–1 was maintained even after 3000 charge–discharge cycles at a current density of 1 A g–1 with an aqueous alkaline solution (6 M KOH) electrolyte, indicating an excellent cycling stability. In addition, the specific volumetric capacitance of Ba2Bi0.1Sc0.2Co1.7O6−δ reaches up to 2549.4 F cm–3 based on the dense construction a...
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b Site Cation ordered double perovskites as efficient and stable electrocatalysts for oxygen evolution reaction
Chemistry: A European Journal, 2017Co-Authors: Gao Chen, Wei Zhou, Zongping ShaoAbstract:Simple disordered perovskite oxides have been intensively exploited as promising electrocatalysts for the oxygen evolution reaction (OER) towards their appliCation in water splitting, reversible fuel cells, and rechargeable metal-air batteries. Here, the B-Site Cation-ordered double perovskites Ba2BixSc0.2Co1.8-xO6-, with two types of cobalt local environments, are demonstrated to be superior electrocatalysts for OER in alkaline solution, demonstrating ultrahigh catalytic activity. In addition, no obvious performance degradation is observed for the Ba2Bi0.1Sc0.2Co1.7O6- sample after a continuous chronopotentiometry test. The critical role of the ordered [Co2+] and [Sc3+, Bi5+, Co3+] dual environments in improving OER activity is exhibited. These results indicate that B-Site Cation-ordered double perovskite oxides may represent a new class of promising electrocatalysts for the OER in sustainable energy storage and conversion systems.
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enhancing electrocatalytic activity of perovskite oxides by tuning Cation deficiency for oxygen reduction and evolution reactions
Chemistry of Materials, 2016Co-Authors: Wei Zhou, Zongping Shao, Yubo Chen, Jie YuAbstract:Development of cost-effective and efficient electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of prime importance to emerging renewable energy technologies. Here, we report a simple and effective strategy for enhancing ORR and OER electrocatalytic activity in alkaline solution by introducing A-Site Cation deficiency in LaFeO3 perovskite; the enhancement effect is more pronounced for the OER than the ORR. Among the A-Site Cation deficient perovskites studied, La0.95FeO3-δ (L0.95F) demonstrates the highest ORR and OER activity and, hence, the best bifunctionality. The dramatic enhancement is attributed to the creation of surface oxygen vacancies and a small amount of Fe4+ species. This work highlights the importance of tuning Cation deficiency in perovskites as an effective strategy for enhancing ORR and OER activity for appliCations in various oxygen-based energy storage and conversion processes.
Hansconrad Zur Loye - One of the best experts on this subject based on the ideXlab platform.
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a family of a Site Cation deficient double perovskite related iridates ln9sr2ir4o24 ln la pr nd sm
Inorganic Chemistry, 2018Co-Authors: Timothy Ferreira, Mark D Smith, Hansconrad Zur LoyeAbstract:The compositions of the general formula Ln11–xSrxIr4O24 (Ln = La, Pr, Nd, Sm; 1.37 ≥ x ≥ 2) belonging to a family of A-Site Cation-deficient double-perovskite-related oxide iridates were grown as highly faceted single crystals from a molten strontium chloride flux. Their structures were determined by single-crystal X-ray diffraction. On the basis of the single-crystal results, additional compositions, Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm), were prepared as polycrystalline powders via solid-state reactions and structurally characterized by Rietveld refinement. The compositions Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) contain Ir(V) and Ir(IV) in a 1:3 ratio with an average iridium oxidation state of 4.25. The single-crystal compositions La9.15Sr1.85Ir4O24 and Pr9.63Sr1.37Ir4O24 contain relatively less Ir(V), with the average iridium oxidation states being 4.21 and 4.09, respectively. The magnetic properties of Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) were measured, and complex magnetic behavior was observed in all cases a...
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A Family of A-Site Cation-Deficient Double-Perovskite-Related Iridates: Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm).
Inorganic Chemistry, 2018Co-Authors: Timothy Ferreira, Mark D Smith, Hansconrad Zur LoyeAbstract:The compositions of the general formula Ln11–xSrxIr4O24 (Ln = La, Pr, Nd, Sm; 1.37 ≥ x ≥ 2) belonging to a family of A-Site Cation-deficient double-perovskite-related oxide iridates were grown as highly faceted single crystals from a molten strontium chloride flux. Their structures were determined by single-crystal X-ray diffraction. On the basis of the single-crystal results, additional compositions, Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm), were prepared as polycrystalline powders via solid-state reactions and structurally characterized by Rietveld refinement. The compositions Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) contain Ir(V) and Ir(IV) in a 1:3 ratio with an average iridium oxidation state of 4.25. The single-crystal compositions La9.15Sr1.85Ir4O24 and Pr9.63Sr1.37Ir4O24 contain relatively less Ir(V), with the average iridium oxidation states being 4.21 and 4.09, respectively. The magnetic properties of Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) were measured, and complex magnetic behavior was observed in all cases a...
Yuichi Ikuhara - One of the best experts on this subject based on the ideXlab platform.
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transmission electron microscopy and scanning transmission electron microscopy study on b Site Cation ordered structures in a 1 x pb mg1 3nb2 3 o3 xpbtio3 single crystal
Applied Physics Letters, 2009Co-Authors: Yukio Sato, Teruyasu Mizoguchi, Naoya Shibata, Hiroki Moriwake, Tsukasa Hirayama, Yuichi IkuharaAbstract:Transmission electron microscopy and scanning transmission electron microscopy were performed to investigate B-Site Cation-ordered structures in a (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (x∼0.30) single crystal. Selected-area diffraction patterns showed presence of F-spots corresponding to 1:1 order. Besides, the F-spots were elongated to be “X”-like in shape. Transmission electron microscopy dark-field images revealed that size of ordered domains was about a few nanometers, and they were dispersed within disordered matrix. Scanning transmission electron microscopy indicated the presence of 1:1 ordered domains. Presence of 1:2 ordered structures was also indicated. These are consistent with features of the selected-area diffraction patterns.
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Transmission electron microscopy and scanning transmission electron microscopy study on B-Site Cation ordered structures in a (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 single crystal
Applied Physics Letters, 2009Co-Authors: Yukio Sato, Teruyasu Mizoguchi, Naoya Shibata, Hiroki Moriwake, Tsukasa Hirayama, Yuichi IkuharaAbstract:Transmission electron microscopy and scanning transmission electron microscopy were performed to investigate B-Site Cation-ordered structures in a (1−x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (x∼0.30) single crystal. Selected-area diffraction patterns showed presence of F-spots corresponding to 1:1 order. Besides, the F-spots were elongated to be “X”-like in shape. Transmission electron microscopy dark-field images revealed that size of ordered domains was about a few nanometers, and they were dispersed within disordered matrix. Scanning transmission electron microscopy indicated the presence of 1:1 ordered domains. Presence of 1:2 ordered structures was also indicated. These are consistent with features of the selected-area diffraction patterns.
Timothy Ferreira - One of the best experts on this subject based on the ideXlab platform.
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a family of a Site Cation deficient double perovskite related iridates ln9sr2ir4o24 ln la pr nd sm
Inorganic Chemistry, 2018Co-Authors: Timothy Ferreira, Mark D Smith, Hansconrad Zur LoyeAbstract:The compositions of the general formula Ln11–xSrxIr4O24 (Ln = La, Pr, Nd, Sm; 1.37 ≥ x ≥ 2) belonging to a family of A-Site Cation-deficient double-perovskite-related oxide iridates were grown as highly faceted single crystals from a molten strontium chloride flux. Their structures were determined by single-crystal X-ray diffraction. On the basis of the single-crystal results, additional compositions, Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm), were prepared as polycrystalline powders via solid-state reactions and structurally characterized by Rietveld refinement. The compositions Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) contain Ir(V) and Ir(IV) in a 1:3 ratio with an average iridium oxidation state of 4.25. The single-crystal compositions La9.15Sr1.85Ir4O24 and Pr9.63Sr1.37Ir4O24 contain relatively less Ir(V), with the average iridium oxidation states being 4.21 and 4.09, respectively. The magnetic properties of Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) were measured, and complex magnetic behavior was observed in all cases a...
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A Family of A-Site Cation-Deficient Double-Perovskite-Related Iridates: Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm).
Inorganic Chemistry, 2018Co-Authors: Timothy Ferreira, Mark D Smith, Hansconrad Zur LoyeAbstract:The compositions of the general formula Ln11–xSrxIr4O24 (Ln = La, Pr, Nd, Sm; 1.37 ≥ x ≥ 2) belonging to a family of A-Site Cation-deficient double-perovskite-related oxide iridates were grown as highly faceted single crystals from a molten strontium chloride flux. Their structures were determined by single-crystal X-ray diffraction. On the basis of the single-crystal results, additional compositions, Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm), were prepared as polycrystalline powders via solid-state reactions and structurally characterized by Rietveld refinement. The compositions Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) contain Ir(V) and Ir(IV) in a 1:3 ratio with an average iridium oxidation state of 4.25. The single-crystal compositions La9.15Sr1.85Ir4O24 and Pr9.63Sr1.37Ir4O24 contain relatively less Ir(V), with the average iridium oxidation states being 4.21 and 4.09, respectively. The magnetic properties of Ln9Sr2Ir4O24 (Ln = La, Pr, Nd, Sm) were measured, and complex magnetic behavior was observed in all cases a...
Changsheng Deng - One of the best experts on this subject based on the ideXlab platform.
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the effect of a Site Cation ln la pr sm on the crystal structure conductivity and oxygen reduction properties of sr doped ferrite perovskites
Solid State Ionics, 2012Co-Authors: Rainer Kungas, Raymond J Gorte, Changsheng DengAbstract:Abstract The influence of A-Site Cation (Ln = La, Pr, Sm) on the crystal structure of Sr-doped ferrite perovskites (Ln 0.8 Sr 0.2 FeO 3 − δ , LnSF) was studied and the results used to interpret the differences in electronic conductivity. The electronic conductivity decreased with decreasing A-Site Cation radius, i.e. in the order La > Pr > Sm between 573 K and 1173 K, whereas the ionic conductivity increased in the order La 0.8 Sr 0.2 FeO 3 − δ (PSF) was more than one order of magnitude higher than that of La 0.8 Sr 0.2 FeO 3 − δ (LSF) at 973 K. To evaluate these materials as cathode materials for solid oxide fuel cells (SOFCs), the chemical compatibility of LnSF with yttria-stabilized zirconia (YSZ) was investigated. Despite significant differences in ionic and electronic conductivity, the performance of the symmetric cells with compoSite cathodes formed by infiltration of doped LnFeO 3 into YSZ and calcination to 1123 K were essentially independent of the transport properties of the cathode materials, exhibiting an identical impedance of 0.08 Ω∙cm 2 at 973 K.
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The effect of A-Site Cation (Ln = La, Pr, Sm) on the crystal structure, conductivity and oxygen reduction properties of Sr-doped ferrite perovskites
Solid State Ionics, 2012Co-Authors: Rainer Kungas, Raymond J Gorte, Changsheng DengAbstract:Abstract The influence of A-Site Cation (Ln = La, Pr, Sm) on the crystal structure of Sr-doped ferrite perovskites (Ln 0.8 Sr 0.2 FeO 3 − δ , LnSF) was studied and the results used to interpret the differences in electronic conductivity. The electronic conductivity decreased with decreasing A-Site Cation radius, i.e. in the order La > Pr > Sm between 573 K and 1173 K, whereas the ionic conductivity increased in the order La 0.8 Sr 0.2 FeO 3 − δ (PSF) was more than one order of magnitude higher than that of La 0.8 Sr 0.2 FeO 3 − δ (LSF) at 973 K. To evaluate these materials as cathode materials for solid oxide fuel cells (SOFCs), the chemical compatibility of LnSF with yttria-stabilized zirconia (YSZ) was investigated. Despite significant differences in ionic and electronic conductivity, the performance of the symmetric cells with compoSite cathodes formed by infiltration of doped LnFeO 3 into YSZ and calcination to 1123 K were essentially independent of the transport properties of the cathode materials, exhibiting an identical impedance of 0.08 Ω∙cm 2 at 973 K.
