Biomimetic Cu4 Cluster Encapsulated within Hollow Titanium-Oxo Nanoring for Electrochemical CO2 Reduction to Ethylene

The construction of biomimetic cluster catalysts with metalloenzyme-like active sites may open an avenue for the challenging transformation of greenhouse gases (e.g., CO2) to high-value chemicals. Cu-enzymes occur in all three biological kingdoms, with CuZ clusters serving as representative reaction sites that catalyze challenging transformations. However, artificial Cu clusters with analogous CuZ structures and high stability are still rare. In this work, we have successfully adopted a Ti9-oxo nanoring as an inorganic templating scaffold to isolate a small Cu4 cluster, which can be regarded as a atomically precise bioinspired cluster with metalloenzyme-like catalytic sites (CuZ). Importantly, Cu4@Ti9 displays high selectivity for the electrocatalytic reduction of CO2 to C2H4 (FE: 47.6 ± 3.4%) at 400 mA cm–2 and good catalytic durability (8 h). The bioinspired Cu4@Ti9 not only represents the first example of Cu cluster directly encapsulated by a metal-oxo shell but also opens the CO2 electroreduction to ethylene applications of atomically precise metallic clusters.