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

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\u202fs) by applying square wave potential pulses (between 0.2\u202fV and −1.7\u202fV vs. SMSE) to treat a smooth Cu-Ni-Zn disk electrode in a 2\u202fM NaOH solution. The oxidation products of Zn(OH)42−, CuOOH and NiOOH at 0.2\u202fV 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\u202fV, 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\u202fμM), high sensitivity (3624\u202fμA\u202fmM−1\u202fcm−2), wide linear range (2\u202fμM–6.1\u202fmM), long-term stability (five-week storage), and accurate analysis of glucose in human blood.