Atomic-scale interfacial engineering enables high-performance electrochemical glucose detection

Developing noble-metal free electrocatalysts with high sensitivity is critical for the large-scale application of electrochemical glucose sensors. This work reports an atomic-scale interfacial engineering strategy to construct highly-active electrocatalyst for glucose detection. Ni(OH)₂ nanosheets are decorated with an ultra-thin layer of Co₉S₈ using the atomic layer deposition (ALD) technique. After in-situ reconstruction, we obtain Ni@Co heterostructure composed of Ni hydroxide nanosheets and CoO_x clusters, which exhibits outstanding electrochemical glucose sensing performance. Combining synchrotron-based X-ray adsorption spectroscopy, in situ Raman Spectroscopy, intermittent electrochemical measurements and density functional theory (DFT) calculations, we find that the presence of surface CoO_x not only lowers the valence state of Ni, but also facilitates the deprotonation of Ni(OH)₂ to form NiOOH active species for glucose oxidation. The approach used in this work can be adapted to synthesizing high-performance electrocatalysts for other energy and environmental devices.