Electrocatalytic Rate Alignment Enhances Syngas Generation

Electrocatalytically generating synthesis gas (syngas, CO + H2) from aqueous CO2 requires balancing the relative rates of CO and H2 generation such that the needed range of desired syngas compositions can be achieved. By purposely integrating two distinct catalytic materials, one for H2 generation and one for CO generation, we deliberately aligned the rates of these two reactions, thereby enhancing syngas tunability as a function of potential. A modular synthetic approach enabled the systematic surface decoration of Au nanostructured electrocatalysts with a series of 3d transition metals, Co, Ni, and Fe, which augmented the selective CO generation of the Au substrate with rapid H2 generation. The resulting rate-aligned electrocatalyst generates—in contrast with the non-rate-aligned control—a wide range of desirable syngas compositions over a 200 mV range, all at current densities greater than 50 mA/cm2.