Publications by authors named "Ryohji Ohnishi"

Humid CO adsorption in K-exchanged zeolites featuring double-eight membered ring (D8R) structures results in CO outcompeting and desorbing dimeric water under equilibrated conditions, which is not observed for either the H-form of the same zeolites or larger-pore zeolites.

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Small-pore zeolites are gaining increasing attention owing to their superior catalytic performance. Despite being critical for the catalytic activity and lifetime, postsynthetic tuning of bulk Si/Al ratios of small-pore zeolites has not been achieved with well-preserved crystallinity because of the limited mass transfer of aluminum species through narrow micropores. Here, we demonstrate a postsynthetic approach to tune the composition of small-pore zeolites using a previously unexplored strategy named pore-opening migration process (POMP).

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The strong affinity of water to zeolite adsorbents has made adsorption of CO from humid gas mixtures such as flue gas nearly impossible under equilibrated conditions. Here, in this manuscript, we describe a unique cooperative adsorption mechanism between HO and Cs cations on Cs-RHO zeolite, which actually facilitates the equilibrium adsorption of CO under humid conditions. Our data demonstrate that, at a relative humidity of 5%, Cs-RHO adsorbs 3-fold higher amounts of CO relative to dry conditions, at a temperature of 30 °C and CO pressure of 1 bar.

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A Li-O(2) battery with TiN nanoparticles supported on Vulcan XC-72, n-TiN/VC, as the cathode catalyst presented an onset potential for the oxygen evolution reaction (OER) at 2.9 V, contrasting with a mixture of micro-sized TiN and VC (m-TiN/VC), and VC, both at ~3.1 V.

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The direct synthesis of TiN nanoparticles on carbon black (CB) was achieved using an mpg-C(3)N(4)/CB composite as a template. The obtained TiN/CB composites ensured improved contact between TiN and CB, functioning as an efficient cathode catalyst for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). The preparation procedure developed in this study is applicable for the synthesis of a variety of supported nano-nitride catalysts.

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