Retaining the high-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 at room temperature


  • Chatr Panithipongwut KOWALSKI Research Unit of Advanced Materials for Energy Storage, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand


Solid acids, Rb3H(SO4)2, Rb5H3(SO4)4, Phase transition, Quenching


The attempts to maintain the higher-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 were demonstrated in this work for the first time. The goal was to explore the possibility to utilize solid acids at lower temperatures while keeping the high-temperature phases which connects to the desirable conductivities. Enabling to do so will allow the ease of handling and thermal cycling, and the energy saving in fuel cell applications, and will allow researchers to study the high-temperature properties of solid acids at lower temperatures without the expenses for the in-situ measurements and the accessibility limitations. The four relatively simple methods, which were the oven, the active airflow, the dry ice, and the liquid nitrogen methods, were selected to compare with the natural cooling at the room temperature. The dry ice and the liquid nitrogen methods for both Rb3H(SO4)2 and Rb5H3(SO4)4 could not preserve the high-temperature structures at all. The other three methods worked poorly for Rb3H(SO4)2, but quite well for Rb5H3(SO4)4. The oven method was the best to retain one of the Rb5H3(SO4)4 structures and no evidence of the original phases formed until several days later, revealing the possibility to use and study Rb5H3(SO4)4 at lower temperatures in the future.


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How to Cite

C. P. . KOWALSKI, “Retaining the high-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 at room temperature”, J. Met. Mater. Miner., vol. 31, no. 4, pp. 116-122, Dec. 2021.



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