Effect of the calcination temperature on the structure and performance of Nickel-Iron-oxide catalysts for application in anion-exchange membrane electrolyzers

In our paper, we present the results of the heating treatments on synthesized catalysts, based on Ni and Fe oxides, with controlled air calcination performed at 350°C, 450°C, and 550°C for 2h, in a furnace with a heating rate of 10°C/min. The objective is to determine the effect of the calcination temperature on the structure, composition, particle size, and catalytic activity of the obtained species. Morphological analyses were performed by Transmission Electron Microscopy (TEM). The structure and the surface composition were evaluated by X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The electrochemical characterization was first performed by the Rotating Disc Electrode (RDE). Then, the catalysts were deposited by spray coating technique onto a Fumasep® FAA3-50 anion-exchange membrane to realize a catalyst-coated membrane (CCM) and tested in a 5 cm2 single cell setup (zero-gap approach) supplying a 1 M KOH solution to the anode side [1]. The obtained results were finally compared in order to identify the optimal conditions for the synthesis process. The behaviour of the catalysts was then compared with the performance shown by commercial catalysts (NiO and IrO2) tested under the same conditions.