Tuning CoPi stability in electrochemical water oxidation via surface modification with an organic ligand shell

In electrocatalytic applications, catalyst interface crucially influences electrochemical activity and selectivity, balancing adsorption, desorption, and transport of intermediates and electrons. Capitalizing on this fact, this study unveils a novel approach to enhance CoO_x surfaces, a promising electrocatalyst for water oxidation, through organic shell functionalization via electrodeposition. Utilizing a dinuclear cobalt complex 1, resembling CoO_x's structure, we crafted a modified film exhibiting remarkable stability. This film consistently delivered a current density of 2.0 mA/cm² for oxygen evolution at 1.5 V vs. NHE, sustaining over 25 h under neutral conditions with only a minimal 5% activity reduction. Conversely, the standard CoPi catalyst underwent rapid deterioration, losing about 40% of its initial catalytic current in just 14 h. Further investigations revealed that the organic shell effectively reduces catalyst dissolution, in contrast to the severe dissolution of CoPi, directly impacting its catalytic activity. This approach offers a straightforward means to functionalize various nanostructured materials, potentially enhancing their electrochemical activities and stabilities.