title: Amine-free reversible hydrogen storage in formate salts catalyzed by ruthenium pincer complex without pH control or solvent change.
abstract: Due to the intermittent nature of most renewable energy sources, such as solar and wind, energy storage is increasingly required. Since electricity is difficult to store, hydrogen obtained by electrochemical water splitting has been proposed as an energy carrier. However, the handling and transportation of hydrogen in large quantities is in itself a challenge. We therefore present here a method for hydrogen storage based on a CO2 (HCO3 (-) )/H2 and formate equilibrium. This amine-free and efficient reversible system (>90 % yield in both directions) is catalyzed by well-defined and commercially available Ru pincer complexes. The formate dehydrogenation was triggered by simple pressure swing without requiring external pH control or the change of either the solvent or the catalyst. Up to six hydrogenation-dehydrogenation cycles were performed and the catalyst performance remained steady with high selectivity (CO free H2 /CO2 mixture was produced).
authors.affiliation: Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, CA 90089-1661 (USA), Fax: (+1) 213-740-5087.
authors.forename: Jotheeswari
authors.initials: J
authors.lastname: Kothandaraman
authors.forename: Miklos
authors.initials: M
authors.lastname: Czaun
authors.forename: Alain
authors.initials: A
authors.lastname: Goeppert
authors.forename: Ralf
authors.initials: R
authors.lastname: Haiges
authors.forename: John-Paul
authors.initials: JP
authors.lastname: Jones
authors.forename: Robert B
authors.initials: RB
authors.lastname: May
authors.forename: G K Surya
authors.initials: GK
authors.lastname: Prakash
authors.forename: George A
authors.initials: GA
authors.lastname: Olah
mesh_terms: D000588:Amines / Q000737:chemistry; D001639:Bicarbonates / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D005561:Formates / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006865:Hydrogenation; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011312:Pressure; D012428:Ruthenium / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*
chemical_list: D000588:Amines; D001639:Bicarbonates; D005561:Formates; D009942:Organometallic Compounds; D012997:Solvents; C030544:formic acid; D002245:Carbon Dioxide; D012428:Ruthenium; D006859:Hydrogen
keywords: PNP ligand; carbon-neutral cycle; energy storage; hydrogenation; ruthenium