Stainless steel supported NiCo2O4 active layer for oxygen evolution reaction

Author(s)

Perroni, P. B. ; Ferraz, T. V. B. ; Rousseau, J. ; Canaff, C. ; Varela, H. ; Napporn, T. W.

• Document type: Journal article
• Source: Electrochimica Acta; v. 453, p. 10-pg., 2023-04-07.

Abstract

The energy demand from a clean, renewable and cheap source has been increasingly urgent. In this work, a simple two steps preparation method was used to obtain NiCo2O4. NiCo2O4 layer was electrodeposited and calcined on two different stainless-steel alloys AISI 304 and AISI 316 L. The samples were characterized with XRD and XPS, which confirmed the material to be NiCo2O4. In both substrates the results suggest that the cat-alysts obtained, have good activity for OER, with an overpotential at 10 mA cm-2 of 360 and 340 mV for SS304 and SS316L respectively. However, the OER curve of the layer on SS316L achieves higher current density of 41.7 mA cm-2 while that on SS304 is 29.7 mA cm-2 at 1.7 V vs. RHE. The Tafel slope value shows better kinetics for the layer on SS304. From the EIS studies and the Nyquist plot the RCT for SS304 is 15.07 omega and for SS316L is 36.74 omega. This can be explained by the higher conductivity of SS304 which promotes the fast growth of nano-flowers with bigger nanopetals during the electrodeposition. The high material density in the surface causes crinkles, as can be seen in SEM analysis. This default in catalysts' morphology leads to a discontinuity in elec-trons transfer through the layer and then a decrease in kinetics. Another hypothesis is the presence of Mo in SS316L, which has a synergistic effect with the other metals. In this latter case the stainless-steel composition would have a direct influence on the reaction kinetics. (AU)

• FAPESP's process: 19/22183-6 - Electrocatalysis VI: fundamental and applied aspects of emerging and classical problems in electrochemical energy conversion
• Grantee: Edson Antonio Ticianelli
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program