Surface-Engineered α-ZrP Nanoplatelets as a Platform for Cobalt-Based Oxygen Evolution Electrocatalysis

In this study, we report a surface-engineering strategy that transforms layered α-zirconium phosphate (α-ZrP) nanoplatelets into an expanded and chemically robust two-dimensional (2D) platform for the oxygen evolution reaction (OER). Covalent grafting with diamino organosilanes introduces pendant amine functionalities that serve as well-defined coordination sites, enabling strong immobilization and controlled nucleation of cobalt species. Structural and spectroscopic analyses reveal substantial interlayer expansion together with the preferential formation of a surface-confined Co(OH)2 phase on the functionalized α-ZrP framework. Under alkaline OER conditions, the catalyst undergoes in situ electrochemical reconstruction to form catalytically active CoOOH species, which constitute the operative phase during water oxidation. The resulting Co-am-ZrP electrocatalyst delivers low overpotentials of 278 and 327 mV at current densities of 10 and 50 mA cm–2, respectively, together with a Tafel slope of 64.7 mV dec–1, indicative of favorable OER kinetics. Moreover, the catalyst maintains stable electrocatalytic activity over 50 h of continuous operation without significant performance loss. This work establishes functionalized α-ZrP nanoplatelets as versatile and robust 2D scaffolds for the rational design of earth-abundant electrocatalysts and highlights the critical role of synergistic ligand–metal–support interactions within covalently engineered layered architectures in regulating cobalt speciation and electrochemical reconstruction behavior.