Scheme 6. Fermi level equilibration between polarized electrodes and metallic NPs that “land” or “impact” on the electrode surface. (A) Oxidative dissolution of NPs by lowering their Fermi levels on impact with a positively polarized electrode. (B) “Electrocatalytic amplification” of metallic NP impacts by raising ENPF on impact and thereby electrocatalyzing a reduction reaction that is kinetically limited on the electrode surface. (C) The NP enhanced tunnelling of electrons through the insulating layer, lowering ENPF on impact and thereby electrocatalyzing an oxidation reaction that does not happen without the NP.