Simultaneous quantification of hydride ions and electrons incorporated in 12CaO·7Al2O3 cages by deuterium-labeled volumetric analysis

Year: 2012 DOI: 10.1021/jp2106742

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Toshihiro Yoshizumi, Yoji Kobayashi, Hiroshi Kageyama, Katsuro Hayashi.   Journal of Physical Chemistry C2012, 116, 8747-8752.


An extended volumetric method, combined with quadrupole mass spectroscopy (QMS), is proposed. This method enables us to distinguish and simultaneously quantify hydride (H-) ions and electrons (e-) incorporated in cages of 12CaO∙Al2O3 (C12A7), which is accomplished upon annealing with CaH2. When a sample is dissolved in a deuterium chloride soln., most of the H- ions and electrons released from cages react to form HD and D2 mols., resp. These isotope-labeled mols. are then detected by QMS. We have used this method to follow the concns. of H- ions and electrons in C12A7 treated CaH2 over the thermal treatment time. We found that during the initial seven days of treatment, both concns. increased. Thereafter, the electron concn. begins to decrease, while the H- ion concn. continues to increase towards the theor. max. This diverging behavior is due to differences in their diffusion ratios and thermodn. stabilities. [on SciFinder(R)]