Controllable voltammetric formation of a structurally disordered NiOOH/Ni(OH)2 redox pair on Ni-nanowire electrodes for enhanced electrocatalytic formaldehyde oxidation. (1st December 2020)

• Record Type: Journal Article
• Authors: Trafela, Špela; Zavašnik, Janez; Šturm, Sašo; Žužek Rožman, Kristina
• Is Part Of: Electrochimica acta. Volume 362(2020)
• Publication Date: 2020-12-01
• Subjects: Nickel -- Nanowires -- Nickel hydroxide -- Formaldehyde -- Electrocatalysis; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.137180
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: In present work, we report on the enhanced electrocatalytic activity of formaldehyde oxidation in alkaline media for modified Ni nanowires (NWs)-based electrodes. Electrochemically deposited Ni NWs composed of metallic Ni and surface NiO were modified in KOH via cyclic voltammetry using different scan rates (10, 200 and 400 mV s −1 ) in order to transform an inactive NiO to the surface-catalytic-active structurally disordered β-NiOOH/β-Ni(OH)2 . Various characterisations (XRD and FT-IR) and calculations based on the electric charge were performed to understand the surface transformations which were found to be scan-rate dependant. The cyclic voltammetry results and kinetic parameters (Tafel plot) of formaldehyde oxidation revealed the superior electrocatalytic activity of the Ni-NW-electrode modified at 200 mV s −1 . The enhanced electrocatalytic performance, i.e., decreased onset overpotential by 400 mV when compared to Ni-based electrocatalysts, of this electrode was attributed to the thickness of structurally disordered the Ni–NiOOH/Ni(OH)2 and composite layered structure that enables the electron injection to reduce the NiOOH work function and thus promote the catalysis of formaldehyde oxidation. The proposed technique provides advances with a novel synthesis strategy for the preparation of highly active, structurally disordered β-Ni(OH)2 /β-NiOOH redox systems on the surface of Ni-based nanostructured electrocatalysts for HCHO oxidation. Graphical abstract: Image, graphical abstract