PNNL

Abstract

Electrocatalytic reversibility represents the ultimate energy efficiency of an electrocatalyst and is achieved when the reaction of interest occurs with fast rates and minimal overpotential. This phenomenon is commonly observed with redox active enzymes and has been extensively pursued with synthetic molecular catalysts as a route to enable high-performing, more robust catalysts for applications in renewable energy. Only recently has reversible catalysis for the oxidation/production of H2 been achieved using synthetic molecular catalysts. Critical to achieving reversibility is the incorporation of an enzyme-inspired, outer coordination sphere that works in concert with both first and second coordination spheres. In this perspective, we discuss a series of molecular H2 production/oxidation catalysts that exhibit electrochemical reversibility. These systems provide insight into the fundamentals required for design principles that can be utilized to achieve efficient catalysis for the conversion of H2, and provide direction for developing electrocatalysts for the conversion of other small molecules.