Copper-nickel combinatorial library screening for electrocatalytic formaldehyde oxidation

Abstract

The electrocatalytic behaviour of a thermally evaporated Cu-Ni thin film combinatorial library was investigated by screening the entire compositional spread in alkaline solution using flow-type scanning droplet cell microscopy. Crystallographic properties and surface microstructure were investigated using XRD and SEM. The obtained Cu-Ni thin film alloys (1-13 at.% Ni) showed suitability for being used in formaldehyde detection. The electrochemical performance of the thin film electrodes was investigated by cyclic voltammetric and chronoamperometric measurements. The highest electrocatalytic effect was found for Cu-6.9 at.% Ni. The concept of a formaldehyde sensor using Cu-6.9 at.% Ni was tested. The identified alloy showed good performance for formaldehyde detection in a wide linear range (3-200 mM), high reproducibility (relative standard deviation $6%), longterm stability and sensitivity to formaldehyde oxidation.

Voltammetric behaviour of Cu alloys toward hydrogen peroxide and organic species

“…Similarly to the case of ethanol, the current density is much higher than in other Cu alloys reported in the literature (see, e.g., ref. [2,[44][45][46]). The oxidation process occurs at potential values close to the Ni(II)/Ni(III) redox process, indicating the active role of this metal in formaldehyde oxidation process.…”