Catalysis

Oxygen evolution

Polymer chemistry

Electrochemistry

Photochemistry

Cyclic voltammetry

Molecular oxygen

Biochemistry

Inorganic chemistry

Physical chemistry

Organic chemistry

Porphyrin

Oxygen

Monolayer

Cobalt

Chemistry

Electrode

Journal of the American Chemical Society

We report an electrochemical scanning tunneling microscopy (ECSTM) study of the 5,10,15,20-tetraphenyl-21H,23H-porphyrin cobalt(II) (CoTPP) catalyzed oxygen evolution reaction (OER). A highly ordered self-assembled monolayer of CoTPP is formed on the Au(111) electrode. Cyclic voltammetry results show the OER activity of the electrode is enhanced with the increasing alkalinity of the electrolytes. The CoTPP molecules appear as two symmetric bright spots in STM images in alkaline solution, which is in sharp contrast to that in acidic solution. The molecular contour changes are attributed to the formation of the CoTPP–OH– species before OER, which is further confirmed by UV–vis absorption spectroscopy. In situ ECSTM results reveal the evolution from the CoTPP–OH– species to CoTPP molecules during OER.

Molecular Evidence for the Catalytic Process of Cobalt Porphyrin Catalyzed Oxygen Evolution Reaction in Alkaline Solution