CO2 Electroreduction To Syngas With Tunable Composition In An Artificial Leaf**

Abstract

AbstractArtificial leaves (a‐leaves) can reduce carbon dioxide into syngas using solar power and could be combined with thermo‐ and biocatalytic technologies to decentralize the production of valuable products. By providing variable CO : H2 ratios on demand, a‐leaves could facilitate optimal combinations and control the distribution of products in most of these hybrid systems. However, the current design procedures of a‐leaves concentrate on achieving high performance for a predetermined syngas composition. This study demonstrates that incorporating the electrolyte flow as a design variable enables flexible production without compromising performance. The concept was tested on an a‐leaf using a commercial cell, a Cu2O:Inx cathodic catalyst, and an inexpensive amorphous silicon thin‐film photovoltaic module. Syngas with CO : H2 ratio in the range of 1.8–2.3 could be attained with only 2 % deviation from the optimal cell voltage and controllable solely by catholyte flow. These features could be beneficial for downstream technologies such as Fischer‐Tropsch synthesis and anaerobic fermentation.