Figure 6: Application of mechanical strain to enhance the methanation reaction on Ni.
From: Mechanical work makes important contributions to surface chemistry at steps
(a) Binding energy changes versus biaxial strain for the reactant CO and product C+O on Ni; compression increases binding of CO and is controlled by the mechanical contribution, while both mechanical and electronic contributions contribute to binding of C+O. (b) Resulting CO dissociation reaction energy Ediss[CO] on Ni, showing a strong variation with strain due to the difference in behaviour between reactant and product shown in a. (c) Methanation activity versus Ediss[CO] (black lines: volcano plot computed in refs 34, 35; solid squares: experimental/computational results of Andersson et al. on unstrained Ni, Rh, Ru, Co and Fe; error bars according to ref 34; blue circles: current predictions for Ni under biaxial strain using results from 0 to 3 % in steps of 0.5%. Biaxial strain (+3%) in Ni can move the Ni activity up to the peak activity of the volcano plot. Strain can thus make the suboptimal catalyst Ni optimal, and shift the activity of Ni to be equal to the activity of Co or Ru.
