Construction of bimetallic oxy-hydroxides based on Ni(OH)₂ nanosheets for sensitive non-enzymatic glucose detection <i>via</i> electrochemical oxidation and incorporation

Due to their ease of synthesis and large specific surface area, Ni(OH)₂ nanosheets have emerged as promising electrochemical sensing materials, attracting significant attention in recent years. Herein, a series of oxy-hydroxides based on Ni(OH)₂ nanosheets, including NiO_<i>x</i>/Ni(OH)₂@NF and (MNi)O_<i>x</i>/Ni(OH)₂@NF (M = Co, Fe, or Cr), are successfully synthesized <i>via</i> the electrochemical oxidation and incorporation strategies. Electrochemical tests demonstrate that these Ni(OH)₂-based oxy-hydroxides exhibit excellent electrochemical oxidation activity for glucose in alkaline electrolyte. Among these, (CoNi)O_<i>x</i>/Ni(OH)₂@NF displays higher sensitivity of 3590.3 μA mM^-1 cm^-2 across a broad linear range of 10 μM to 1.14 mM, with a rapid current response time of less than 4 s. The superior sensing performances of (CoNi)O_<i>x</i>/Ni(OH)₂@NF are attributed to the formation of abundant Ni³⁺ species and reactive-O atoms due to the electrochemical oxidation, and the synergistic effects of Co/Ni active sites resulting from the electrochemical incorporation process. In addition, the (CoNi)O_<i>x</i>/Ni(OH)₂@NF demonstrates good stability and reproducibility for glucose sensing. This work fully leverages the significance of surface reconstruction of Ni(OH)₂, providing new insights for the application of transition metal-based oxy-hydroxide materials in bio-sensing.