Rhodium dihydride (RhH2) with high volumetric hydrogen density.
Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH(2)) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH(2) at 8 GPa. RhH(2) is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH(2) is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time.
State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
Bing
B
Li
Yang
Y
Ding
Duck Young
DY
Kim
Rajeev
R
Ahuja
Guangtian
G
Zou
Ho-Kwang
HK
Mao
D002621:Chemistry / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods; D004563:Electrochemistry / Q000379:methods; D004581:Electronics; D006859:Hydrogen / Q000737:chemistry*; D007700:Kinetics; D010825:Physics / Q000379:methods; D011312:Pressure; D012238:Rhodium / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012984:Software; D013696:Temperature
D012965:Sodium Chloride; D006859:Hydrogen; D012238:Rhodium