In-situ dynamic reconstruction of catalyst surface during water electrolysis determines the active species and further enhances the catalytic performance. However, rationally modulating the dynamic surface restructuring and generating active surface species remain tremendous challenges. In this work, we present a novel cationic redox-tuning method to redirect the in-situ surface reconstruction of a transition-metal-oxide electrocatalyst for the oxygen evolution reaction (OER). Cl-doping tuned the electronic structures of LiCoO2, switches Co redox, and facilitates dynamic Li extraction during OER cycles. The doping concentration governed the surface reconstruction pathway between thermodynamic versus kinetic control of reaction. (e.g. spinel-type or amorphous (oxy)hydroxide). Various synchrotron-based analysis including operando X-ray absorption spectroscopy assessed working principles in detail. The surface was self-terminated promptly and sustained the high activity for 500 h without degradation. This work makes a stride in modulating surface restructuring and opens up new opportunities to design superior OER electrocatalysts via tuning cationic redox.

Manipulating dynamic surface transformation of electrocatalysts for superior water oxidation

ACS Fall 2021

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