Effect of CO2 on hydrogen absorption in Ti-Zr-Mn-Cr based AB2 type alloys

• DOI: 10.1016/j.jallcom.2017.02.067
• Publication Date: 2017-02-09T09:46:32Z
• Authors: Nobuko Hanada; Hirotaka Asada; Tessui Nakagawa; Hiroki Higa; Masayoshi Ishida; Daichi Heshiki; Tomohiro Toki; Itoko Saita; Kohta Asano; Yumiko Nakamura; Akitoshi Fujisawa; Shinichi Miura
• Keywords: 0202 electrical engineering, electronic engineering, information engineering; 02 engineering and technology

Abstract The effect of CO 2 on hydrogen absorption has been investigated for AB 2 type alloys of Ti 0.515 Zr 0.485 Mn 1.2 Cr 0.8 (Ti-Zr-Mn-Cr) and Ti 0.515 Zr 0.485 Mn 1.2 Cr 0.8 M 0.1 (Ti-Zr-Mn-Cr-M, M = Fe, Co, or Ni) in order to develop metal hydrides for a hydrogen purification and storage system. A magnitude of CO 2 poisoning tolerance was evaluated by comparing hydrogen absorption properties before and after CO 2 exposure. As the results, an order of CO 2 tolerance was Ti-Zr-Mn-Cr-Ni 2 alloys have dependence of additive 3d-transition elements on CO 2 tolerance. Ti-Zr-Mn-Cr-Fe has the highest CO 2 tolerance among them. The additive of Fe and Co improves tolerance of CO 2 poisoning for hydrogen absorption properties. On the other hand, Ni element in AB 2 alloy decreases CO 2 tolerance. The estimated enthalpy change between CO 2 and the alloys surface was comparable to the formation of metal oxide. And the CO 2 -exposed AB 2 alloys after reacting with hydrogen desorbed methane gas. Therefore, CO 2 would dissociate to CO and O on the surface of alloys, and then oxygen atom reacts with the alloys.