Electrochemical treating of a smooth Cu-Ni-Zn surface into layered micro-chips of rice grain-like Cu/Ni(OH)2 nanocomposites as a highly sensitive enzyme-free glucose sensor

Abstract

Herein, a novel thin film of layered micro-chips of compact rice grain-like Cu/Ni(OH)2 nanocomposites has been fabricated via a new electrochemical route. It is achieved in a short time (1500 s) by applying square wave potential pulses (between 0.2 V and −1.7 V vs. SMSE) to treat a smooth Cu-Ni-Zn disk electrode in a 2 M NaOH solution. The oxidation products of Zn(OH)42−, CuOOH and NiOOH at 0.2 V from the Cu-Ni-Zn electrode surface are dissolved in the solution and reduced to nanocomposites of Cu nanowires and Ni(OH)2 nanosheets at −1.7 V, respectively. The presence of Zn in the alloy and its dissolution from the alloy surface play the key role for the formation of the layered micro-chips. The layered micro-chips of rice grain-like Cu/Ni(OH)2 nanocomposites enlarge the active surface area of the thin film, which enhances the electro-oxidation of glucose and the performance in sensing glucose. The prepared thin film of micro-chips of Cu/Ni(OH)2 nanocomposites can serve as an advanced non-enzymatic glucose sensor. It has these merits of low detection limit (0.37 μM), high sensitivity (3624 μA mM−1 cm−2), wide linear range (2 μM–6.1 mM), long-term stability (five-week storage), and accurate analysis of glucose in human blood.