DNA-Anchored Single-Molecule Iron Phthalocyanine As an Efficient Electrocatalyst for Alkaline Fuel Cells

Abstract

Molecular catalysts have attracted significant attention because of their high activity, selectivity, and tunability. However, in heterogeneous catalysis, the uniform dispersion and immobilization of molecular catalysts on the supporting substrate remain a significant challenge due to their aggregation tendency. Here, we present a facile strategy to molecularly disperse and immobilize a series of macrocyclic metal complexes onto reduced graphene oxide (rGO) by using DNA as a mediator. The electroactive amounts of molecularly dispersed iron phthalocyanine (FePc) molecules are increased by ∼50 times greater than that of pristine FePc catalyst. As a result, the single-molecule catalyst demonstrates a notable power density (∼290 mW cm –2 ) in an H 2 /O 2 alkaline polymer electrolyte fuel cell. Operando X-ray absorption spectroscopy experiments combined with density functional theory calculations reveal that the coordination interaction between FePc and DNA enables the molecular dispersion and immobilization of FePc on the surface of rGO, and consequently improves the activity by regulating the electronic structure of active centers. This study points out a facile strategy to tackle the fundamental challenges facing molecular catalysts in long-lasting energy conversion technologies.