Zn–Cu Alloy Nanofoams as Efficient Catalysts for the Reduction of CO₂ to Syngas Mixtures with a Potential-Independent H₂/CO Ratio

Graphical Abstract

A certain ratio: A series of bimetallic Zn–Cu electrodes are prepared and used for the production of syngas by electroreduction of CO₂. A broad range of H₂/CO ratios is obtained, which is independent of the applied potential.

Abstract

Alloying strategies are commonly used to design electrocatalysts that take on properties of their constituent elements. Herein, such a strategy is used to develop Zn–Cu alloyed electrodes with unique hierarchical porosity and tunable selectivity for CO₂ versus H⁺ reduction. By varying the Zn/Cu ratio, tailored syngas mixtures are obtained without the production of other gaseous products, which is attributed to preferential CO- and H₂-forming pathways on the alloys. The syngas ratios are also significantly less sensitive to the applied potential in the alloys relative to pure metal equivalents; an essential quality when coupling electrocatalysis with renewable power sources that have fluctuating intensity. As such, industrially relevant syngas ratios are achieved at large currents (−60 mA) for extensive operating times (>9 h), demonstrating the potential of this strategy for fossil-free fuel production.