Herein, we have demonstrated the control over the structure of precatalysts to tune the properties of the active catalysts and their water oxidation activity. The reaction of K3[Fe(CN)6] and Na2[Fe(CN)5(NO)] with Co(OH)2@CC produced precatalysts PC-1 and PC-2, respectively, with distinct structural and electronic features. The replacement of the −CN group with strong π-acceptor −NO modulates the electronic and atomic structure of PC-2. As a result, a facile electrochemical transformation of PC-2 into active catalyst Fe−Co(OH)2-Co(O)OH (AC-2) has been attained only in 15 CV cycles while 600 CV cycles are required for the electrochemical activation of PC-1 into AC-1. The X-ray absorption studies reveal the contraction of the Co−O and Fe−O bond in AC-2 because of the presence of a higher amount of Co3+ and Fe3+ than in AC-1. The high valent Co3+ and Fe3+ modulates the electronic properties of AC-2 and assists in the O−O bond formation, leading to the improved water oxidation activity.
