The chemical activity of metal compound nanoparticles: Importance of electronic and steric effects in M ₈C ₁₂ (M=Ti, V, Mo) metcars

Density functional theory was employed to investigate the chemical activity of metal carbide nanoparticles. The present calculations indicate that M ₈C ₁₂ (M=Ti, V, Mo) nanoparticles exhibit a unique behavior compared to metal [M(001)] and metal carbide surfaces [M ₂C(001) and MC(001)]. It is found that the nanoparticles behave very reactive in spite of the high carbon concentration in some reactions, while surprisingly inert in other cases. Our study reveals that the unexpected activity is the result of the interplay of shifts in the metal d-bands and distortions in the geometry of the metal carbide nanoparticles.