Catalytic Cleavage of the C-H and C-C Bonds of Alkanes by Surface Organometallic Chemistry: An EXAFS and IR Characterization of a Zr-H Catalyst

Abstract

The catalytic cleavage under hydrogen of the C & singlebond;H and C & singlebond;C bonds of alkanes with conventional catalysts requires high temperatures. Room-temperature hydrogenolysis of simple alkanes is possible on a well-defined and well-characterized zirconium hydride supported on silica obtained by surface organometallic chemistry. The surface structure resulting from hydrogenolysis of (≡SiO)Zr(Np)₃ (Np, neopentyl) was determined from the extended x-ray absorption fine structure (EXAFS) and ¹H and ²⁹Si solid-state nuclear magnetic resonance and infrared (IR) spectra. A mechanism for the formation of (≡SiO)₃Zr-H and (≡SiO)₂SiH₂ and the resulting low-temperature hydrogenolysis of alkanes is proposed. The mechanism may have implications for the catalytic formation of methane, ethane, and lower alkanes in natural gas.