Low temperature synthesis of nano porous 12CaO∙7Al₂O₃ powder by hydrothermal method

Abstract

Single-phase insulating 12CaO∙7Al₂O₃ (C12A7) powder was synthesized using an optimized hydrothermal method. Pure phase of C12A7 was got at a comparatively lower temperature (c.a. 300 °C) than that has been previously reported. The crystallite size of the synthesized C12A7 powder was 7±2 nm. The surface area values calculated for all the samples at a synthesis temperature range of 250-800 °C for 5 h were in the range of about 19-24 m²/g, with pore sizes of 12-20 nm. This low-temperature-based synthetic strategy along with nano porous structures and a high surface area value can facilitate catalyst application.

Keywords

C12A7 / hydrothermal method / low temperature / nano pore

References

[1] Kim SW, Matsuishi S, Miyakawa M, et al. Fabrication of Room Temperature-stable 12CaO·7Al₂O₃ Electride: A Review [J]. J. Mater. Sci: Mater. Electron., 2007, 18: S5-S14.

[2] Hosono H, Hayashi K, Kamiya T, et al. New Functionalities in Abundant Element Oxides: Ubiquitous Element Strategy[J]. Sci. Technol. Adv. Mater., 2011, 12: 1-22.

[3] Toda Y, Yanagi H, Ikenaga E, et al. Work Function of a Room-Temperature, Stable Electride [Ca₂₄Al₂₈O₆₄]⁴⁺(e^–)₄[J]. Adv. Mater., 2007, 19: 3564-3569.

[4] Garcia LFR, Aguilar FG, Sabino MG, et al. Mechanical and Microstructural Characterisation of New Calcium Aluminate Cement [J]. Adv. Appl. Ceram., 2011, 110: 469-475.

[5] Jeevaratnam J, Glasser LSD, Glasser FP. Structure of Calcium Aluminate, 12CaO·7Al₂O₃[J]. Nature, 1962, 194: 764-765.

[6] Lacerda M, Irvine JTS, Glasser FP, et al. High Oxide ion Conductivity in Ca₁₂Al₁₄O₃₃[J]. Nature, 1988, 332: 525-526.

[7] Hayashi K, Matsuishi S, Kamiya T, et al. Occurrence of Superoxide Radical Ion in Crystalline 12CaO·7Al₂O₃ Prepared via Solid-state Reactions[J]. Nature, 2002, 419: 462-465.

[8] Kitano M, Inoue Y, Yamazaki Y, et al. Ammonia Synthesis Using a Stable Electride as an Electron Donor and Reversible Hydrogen Store[J]. Nat.Chem., 2012, 4: 934-940.

[9] Hayashi F, Toda Y, Kanie Y, et al. Ammonia Decomposition by Ruthenium Nanoparticles Loaded on Inorganic Electride C12A7:e^-[J]. Chem. Sci., 2013, 4: 3124-3130.

[10] Honkala K, Hellman A, Remediakis IN, et al. Ammonia Synthesis from First-Principles Calculations[J]. Science, 2005, 307: 555-558.

[11] Toda Y, Hirayama H, Kuganathan N, et al. Activation and Splitting of Carbon Dioxide on the Surface of an Inorganic Electride Material[J]. Nat.Commun., 2013 1-8.

[12] Toda Y, Matsuishi S, Hayashi K, et al. Field emission of Electron Anions Clathrated in Subnanometer-sized Cages in [Ca₂₄Al₂₈0₆₄]⁴⁺(e^-) [J]. Adv. Mater., 2004, 16: 685-689.

[13] CKing PD, Veal TD. Conductivity in Transparent Oxide Semiconductors[J]. J. Phys.: Condens.Matter, 2011, 23: 334214.

[14] Dong Y, Hayashi K, Nozoe H, et al. Chloride-Ion-Stabilized Strontium Mayenite: Expansion of Versatile Material Family[J]. J. Am. Ceram. Soc., 2014, 97: 4037-4044.

[15] Ozawa K, Sakamoto N, Wakiya N, et al. Fabrication of 12CaO·7Al₂O₃ Powders with High Specific Surface Area by Sol-gel and Ball-milling Method[J]. J. Ceram. Soc. Jpn., 2011, 119: 460-463.

[16] Hayashi F, Kitano M, Yokoyama T, et al. Treatment for Conductive 12CaO·7Al₂O₃ Electride Powder by Rapid Thermal Annealing Processing and Its Application to Ammonia Synthesis[J]. Chem Cat Chem, 2014, 6: 1317-1323.

[17] Gong L, Lin Z, Ning S, et al. Synthesis and Characteristics of the C12A7-O^- Nanoparticles by Citric Acid Sol-gel Combustion Method[J]. Mater. Lett., 2010, 64: 1322-1324.

[18] Li C, Hirabayashi D, Suzuki K. Synthesis of Higher Surface Area Mayenite by Hydrothermal Method[J]. Mater. Res. Bull., 2011, 46: 1307-1310.