Tuning the Catalytic Activity of a Quantum Nutcracker for Hydrogen Dissociation

Abstract

A quantum nutcracker, a recently proposed catalytic system for hydrogen dissociation, consists of two inert components: an organic molecule such as a transition metal phthalocyanine and an inert surface such as Cu or Au. The reaction takes place at the interface between the two components, which are weakly bonded by Van der Waals (VdW) forces. Here, we explore a method used to tune the reaction barrier in a quantum nutcracker system for hydrogen dissociation. By employing density-functional-theory calculations, we find that the H2 entry barrier, which is the rate-limiting barrier, is reduced by replacing the phthalocyanine by porphyrin derivatives such as octaethylporphyrin (OEP) and tetraphenylporphyrin (TPP). The system remains active if a dissociated H atom is adsorbed on the transition metal ion. Metallic two-dimensional materials such as NbS2 and CoS2 are good candidates for the quantum nutcracker. The present design of a quantum nutcracker for hydrogen dissociation provides new opportunities with which to induce catalytic activity in VdW-bonded systems.