A Facile Peroxo-Precursor Synthesis Method and Structure Evolution of Large Specific Surface Area Mesoporous BaSnO₃

Abstract

In this paper, we propose a facile and efficient strategy for synthesizing mesoporous BaSnO3 with a surface area as large as 67 m(2)/g using a peroxo-precursor decomposition procedure. As far as we know, this is the largest surface area reported in literature for BaSnO3 materials and may have a potential to greatly promote the technological applications of this kind of functional material in the area of chemical sensors, NOx storage, and dye-sensitized solar cells. The structure evolution of the mesoporous BaSnO3 from the precursor was followed using a series of techniques. Infrared analysis indicates large amount of protons and peroxo ligands are contained in the peroxo-precursor. Although the crystal structure of the precursor appears cubic according to the analysis of X-ray diffraction data, Raman and Mössbauer spectroscopy results show that the Sn atom is offset from the center of [SnO6] octahedron. After calcination at different temperatures, the precursor gradually transforms into BaSnO3 by release of water and oxygen, and the distortion degree of [SnO6] octahedral decreases. However, a number of oxygen vacancies are generated in the calcined samples, which are further confirmed by the physical property measurement system, and they would lower the local symmetry to some content. The concentration of the oxygen vacancies reduces simultaneously as the calcination temperature increases, and their contributions to the total heat capacity of the sample are calculated based on theoretical analysis of heat capacity data in the temperature region below 10 K.

Discovery of Layered Indium Hydroxide via a Hydroperoxyl Anion Coordinated Precursor at Room Temperature

“…In order to investigate the crystallization mechanism, the formation process of layered In(OH) 3 was studied. To the best of our knowledge, Sn 4+ is normally coordinated with OOH − to form precipitates in a hydrogen peroxide (H 2 O 2 ) aqueous solution under basic conditions . Since In 3+ and Sn 4+ have the same electronic configuration, namely 4d 10 , it seems that In 3+ ions also have a strong tendency to be coordinated by OOH − to form precipitates under basic conditions, which was validated by the following experiments.…”

“…To the best of our knowledge, Sn 4 + is normally coordinated with OOH À to form precipitates in ah ydrogen peroxide (H 2 O 2 )a queous solution under basic conditions. [26][27][28] SinceI n 3 + andS n 4 + have the same electronic configuration, namely 4d 10 ,i ts eems that In 3 + ions also have as trong tendency to be coordinated by OOH À to form precipitates under basic conditions, whichw as validated by the following experiments. The0 .1 m indium nitrate hydrogen peroxide aqueouss olution( 30 %H 2 O 2 )w as added into concentrated ammonia water,a nd then formed precipitates with the helpo fS r 2 + .N ote that replacing Sr 2 + by Ca 2 + can also lead to precipitates whichc an then be transformedi nto layered In(OH) 3 ,b ut almost no precipitates were obtained in the similar conditions without the helpo fb ivalent cations.…”

Sn promoted BaFeO3− catalysts for N2O decomposition: Optimization of Fe active centers

“…5) could be well fitted by a single Lorentzian curve, indicating that Sn cations in these catalysts retained homogeneous and unique state. The IS values observed for all these samples lied in the range from 0.00 to 0.08 mm/s, which was characteristic of Sn 4+ species (4d 10 5s 0 5p 0 , IS = -0.4  2.0 mm/s) [59,60] . This result confirmed that Sn ions were exclusively in the +4 oxidation state.…”

Relaxation calorimetry and its application in low temperature specific heat study of solids

“…图 10 纯的和Al掺杂的TiO 2 纳米颗粒1.9~10 K低温摩尔比 热(C/T-T图) [45] (网络版彩图) [52] (网络版彩图) (网络版彩图) Figure 13 Plot of the experimental heat capacities of BS-T (T=400, 500, 600, and 800) samples measured over the temperature range from 2 to 300 K. Insets show the data below T=10 K [59] (color online).…”