Beyond CoOx: a versatile amorphous cobalt species as an efficient cocatalyst for visible-light-driven photocatalytic water oxidation.

Cocatalysts play an important role in converting solar energy into chemical energy for photocatalytic water splitting. Herein, a versatile and efficient cocatalyst based on amorphous Co species (a-Co-E) is synthesized through thermal treatment of a Co-ethylene diamine tetraacetic acid complex in air at 300 °C. Various Bi-based semiconductors loaded with the a-Co-E cocatalyst exhibit an impressively higher photocatalytic O2 evolution rate than their CoOx-loaded counterparts.