Theoretical Design by First Principles Molecular Dynamics of a Bioinspired Electrode-Catalyst System for Electrocatalytic Hydrogen Production from Acidified Water

Bacterial di-iron hydrogenases produce hydrogen efficiently from water. Accordingly, we have studied by first-principles molecular-dynamics simulations (FPMD) electrocatalytic hydrogen production from acidified water by their common active site, the [FeFe](H) cluster, extracted from the enzyme and linked directly to the (100) surface of a pyrite electrode. We found that the cluster could not be attached stably to the surface via a thiol link analogous to that which attaches it to the rest of the enzyme, despite the similarity of the (100) pyrite surface to the Fe4S4 cubane to which it is linked in the enzyme. We report here a systematic sequence of modifications of the structure and composition of the cluster devised to maintain the structural stability of the pyrite/cluster complex in water throughout its hydrogen production cycle, an example of the molecular design of a complex system by FPMD.