Hi Tahir,

From the theoretical aspect, I would say the delta G value or Volcano plot decide the basic parameters of choosing the proper electrocatalyst. As for example, a good catalyst for hydrogen evolution should fulfill three conditions: delta G -> 0 for hydrogen adsorption, a d band that extends across the Fermi level, and a strong coupling of this band to hydrogen.

And please note that in general, HER catalysts are active in acid solution while OER-ORR catalysts are in alkaline solution. So the material should be flexible in terms of binding H- as well as OH-, simultaneously.

Thank You All....