Both the hydrogen evolution reaction (HER) and
the oxygen evolution reaction (OER) are crucial to water
splitting, but require alternative active sites. Now, a general pelectron-
assisted strategy to anchor single-atom sites (M=Ir,
Pt, Ru, Pd, Fe, Ni) on a heterogeneous support is reported. The
Matoms can simultaneously anchor on two distinct domains of
the hybrid support, four-fold N/C atoms (M@NC), and centers
of Co octahedra (M@Co), which are expected to serve as
bifunctional electrocatalysts towards the HER and the OER.
The Ir catalyst exhibits the best water-splitting performance,
showing a low applied potential of 1.603V to achieve
10 mAcm@2 in 1.0m KOH solution with cycling over 5 h.
DFT calculations indicate that the Ir@Co (Ir) sites can
accelerate the OER, while the Ir@NC3 sites are responsible
for the enhanced HER, clarifying the unprecedented performance
of this bifunctional catalyst towards full water splitting.