Dear Debasis,

It depends on the choice of metal oxide and the electrolyte. In the case of the redox reaction based devices; if reduction reaction takes place within the metal oxide, and the electrolyte then you can say metal oxide as a cathode/ cathodic material and if oxidation reaction takes place within the metal oxide and the electrolyte then you can say metal oxide as an anode/ anodic material.

If anyone has an additional information or way to decide the type of electrode please add / correct .......

Dear Ranjit,

Thanks for your interest. What about if the materials undergoes reversible oxidation and reduction.

Dear Debasis,

If it goes reversible oxidation and reduction still then above explanation stands itself. Reversible oxidation and reduction caused due to applied (positive and negative) potential sweeps to the metal oxide. As a consequence of this, during reversible oxidation and reduction, metal oxide electrode will act as a cathode and anode alternatively.

If you want to decide the type of material (i.e. cathodic or anodic) then you should observe the CV and check whether your M-oxide electrode undergoes oxidation during positive potential sweep or negative potential sweep. Generally if oxidation occurs during positive potential sweep then it will be anodic and vice versa. Hope this will help you.

Dear Ranjit,

Its a very useful information to me. Many thanks.