Alkane activation on crystalline metal oxide surfaces

Advances in the fundamental understanding of alkane activation on oxide surfaces are essential for developing new catalysts that efficiently and selectively promote chemical transformations of alkanes. In this tutorial review, we discuss the current understanding of alkane activation on crystalline metal oxide surfaces, and focus mainly on summarizing our findings on alkane adsorption and C-H bond cleavage on the PdO(101) surface as determined from model ultrahigh vacuum experiments and theoretical calculations. These studies show that alkanes form strongly-bound σ-complexes on PdO(101) by datively bonding with coordinatively-unsaturated Pd atoms and that these molecularly adsorbed species serve as precursors for C-H bond activation on the oxide surface. In addition to discussing the binding and properties of alkane σ-complexes on PdO(101), we also summarize recent advances in kinetic models to predict alkane dissociation rates on solid surfaces. Lastly, we highlight computations which predict that the formation and facile C-H bond activation of alkane σ-complexes also occurs on RuO 2 and IrO 2 surfaces. Late transition-metal oxide surfaces that expose coordinatively-unsaturated metal atoms promote the formation and bond activation of alkane σ-complexes.