The Ce—H.sub.2 redox flow cell is optimized using commercially-available cell materials. Cell performance is found to be sensitive to the upper charge cutoff voltage, membrane boiling pretreatment, methanesulfonic-acid concentration, (+) electrode surface area and flow pattern, and operating temperature. Performance is relatively insensitive to membrane thickness, Cerium concentration, and all features of the (−) electrode including hydrogen flow. Cell performance appears to be limited by mass transport and kinetics in the cerium (+) electrode. Maximum discharge power of 895 mW cm.sup.−2 was observed at 60° C.; an energy efficiency of 90% was achieved at 50° C. The Ce—H.sub.2 cell is promising for energy storage assuming one can optimize Ce reaction kinetics and electrolyte.

Provided are an intermetallic compound having high stability and high activity, and a catalyst using the same. A hydrogen storage/release material containing an intermetallic compound represented by formula (1): RTX . . . (1) wherein R represents a lanthanoid element, T represents a transition metal in period 4 or period 5 in the periodic table, and X represents Si, Al or Ge.

A catalyst used for dehydrogenation of an organic hydrogen-storage material to generate hydrogen, a support for the catalyst, and a preparation process thereof are presented. A hydrogen-storage alloy and a preparation process thereof are provided. A process for providing high-purity hydrogen, a high-efficiently distributed process for producing high-purity and high-pressure hydrogen, a system for providing high-purity and high-pressure hydrogen, a mobile hydrogen supply system, and a distributed hydrogen supply apparatus are also described.

Provided are an intermetallic compound having high stability and high activity, and a catalyst using the same. A hydrogen storage/release material containing an intermetallic compound represented by formula (1): RTX . . . (1) wherein R represents a lanthanoid element, T represents a transition metal in period 4 or period 5 in the periodic table, and X represents Si, Al or Ge.

The CeH.sub.2 redox flow cell is optimized using commercially-available cell materials. Cell performance is found to be sensitive to the upper charge cutoff voltage, membrane boiling pretreatment, methanesulfonic-acid concentration, (+) electrode surface area and flow pattern, and operating temperature. Performance is relatively insensitive to membrane thickness, Cerium concentration, and all features of the () electrode including hydrogen flow. Cell performance appears to be limited by mass transport and kinetics in the cerium (+) electrode. Maximum discharge power of 895 mW cm.sup.2 was observed at 60 C.; an energy efficiency of 90% was achieved at 50 C. The CeH.sub.2 cell is promising for energy storage assuming one can optimize Ce reaction kinetics and electrolyte.

A multi-phase hydrogen storage alloy comprising a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is 30 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % and where the alloy comprises a mischmetal where Nd in the mischmetal is <50 at % or a multi-phase hydrogen storage alloy comprising one or more rare earth elements, a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is from about 30 to about 72 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % have improved electrochemical performance. The alloys are useful in an electrode in a metal hydride battery, a fuel cell or a metal hydride air battery.

A multi-phase hydrogen storage alloy comprising a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is 30 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % and where the alloy comprises a mischmetal where Nd in the mischmetal is <50 at % or a multi-phase hydrogen storage alloy comprising one or more rare earth elements, a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is from about 30 to about 72 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % have improved electrochemical performance. The alloys are useful in an electrode in a metal hydride battery, a fuel cell or a metal hydride air battery.

A multi-phase hydrogen storage alloy comprising a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is 30 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % and where the alloy comprises a mischmetal where Nd in the mischmetal is <50 at % or a multi-phase hydrogen storage alloy comprising one or more rare earth elements, a hexagonal Ce.sub.2Ni.sub.7 phase and a hexagonal Pr.sub.5Co.sub.19 phase, where the Ce.sub.2Ni.sub.7 phase abundance is from about 30 to about 72 wt % and the Pr.sub.5Co.sub.19 phase abundance is 8 wt % have improved electrochemical performance. The alloys are useful in an electrode in a metal hydride battery, a fuel cell or a metal hydride air battery.

Hydrogen storage materials being inexpensive and having hydrogen absorption (storage) and desorption properties suitable for hydrogen storage are provided. The hydrogen storage materials have alloys with an elemental composition of Formula (1), a hydrogen storage container containing the hydrogen storage material, and a hydrogen supply apparatus including the hydrogen storage container:
La.sub.aCe.sub.bSm.sub.cNi.sub.dM.sub.e (1)
wherein M is Mn or both of Mn and Co, a satisfies 0.60a0.90, b satisfies 0b0.30, c satisfies 0.05c0.25, d satisfies 4.75d5.20, e satisfies 0.05e0.40, a+b+c=1, and d+e satisfies 5.10d+e5.35.