Single-atom cobalt centers on various
oxide surfaces (TiO<sub>2</sub>, MgO, SBA-15, AlPO, and Y-Zeolite)
were prepared and evaluated as
water oxidation catalysts by photochemical water oxidation experiments.
Superior catalytic rates were observed for cobalt sites on basic supporting
oxides (TiO<sub>2</sub> and MgO) relative to those on acidic oxides
(Y-Zeolite, AlPO, and SiO<sub>2</sub>). Per-atom turnover frequencies
of ca. 0.04 s<sup>–1</sup> were achieved, giving initial rates
100 times greater than that of a surface atom of a Co<sub>3</sub>O<sub>4</sub> nanoparticle. Contrary to expectations based on theoretical
work, no apparent correlation was observed between the catalytic rates
and the oxygen atom affinities of the supporting oxides
