Ultrasmall Abundant Metal-Based Clusters as Oxygen-Evolving Catalysts

The
oxygen evolution reaction is a crucial step in water electrolysis
to develop clean and renewable energy. Although noble metal-based
catalysts have demonstrated high activity for the oxygen evolution
reaction, their application is limited by their high cost and low
availability. Here we report the use of a molecule-to-cluster strategy
for preparing ultrasmall trimetallic clusters by using the polyoxometalate
molecule as a precursor. Ultrafine (0.8 nm) transition-metal clusters
with controllable chemical composition are obtained. The transition-metal
clusters enable highly efficient oxygen evolution through water electrolysis
in alkaline media, manifested by an overpotential of 192 mV at 10
mA cm–2, a low Tafel slope of 36 mV dec–1, and long-term stability for 30 h of electrolysis. We note, however,
that besides the excellent performance as an oxygen evolution catalyst,
our molecule-to-cluster strategy provides a means to achieve well-defined
transition-metal clusters in the subnanometer regime, which potentially
can have an impact on several other applications.