Stoichiometric and catalytic CO2 reductions involving TiFe-containing intermetallic hydrides

Abstract

Thermoprogrammed desorption of H2 from [TiFe 0.95Zr0.03Mo0.02]H2 showed two forms of absorbed hydrogen. The first one is evolved from the intermetallic hydride under heating up to 185°C under Ar (loosely bound hydrogen, LBH). The second portion of H2 (strongly bound hydrogen, SBH) remains in the intermetallic hydride up to 700-920°C. SBH reacts with CO2 to give CO rather selectively (80-99 %) at CO2 conversion of 50-70 % at 350-430°C and 10-12 atm. Dehydrogenation of cyclohexane coupled with CO 2 hydrogenation into CO predominantly proceeds efficiently in the presence of the intermetallic hydride [TiFe0.95Zr 0.03Mo0.02]Hx (where x ≤ 0.1) in a combination with industrial Pt/Al2O3 catalyst. Aliphatic primary alcohols undergo oxidation by CO2 forming aldehydes in the presence of [TiFe0.95Zr0.03Mo0.02]H 0.36. Conversion of the alcohols into alkanes with carbon skeleton counting at least doubled carbon number in comparison with parent alcohol was found to be catalyzed by the mixture of the last intermetallic hydride and Pt/Al2O3 catalyst.