Properties of SS304 Modified by Nickel–Cobalt Alloy Coating with Cauliflower-Shaped Micro/Nano Structures in Simulated PEMFC Cathode Environment

Abstract

This study presents the corrosion behavior and surface properties of SS304 modified by electrodeposited nickel–cobalt (Ni–Co) alloy coating with cauliflower-shaped micro/nano structures (Ni–Co/SS304) in the simulated PEMFC cathodic environment. The hydrophobicity of the as-prepared Ni–Co alloy coating can be improved simply by low-temperature annealing. The morphology and composition of the Ni–Co/SS304 were analyzed and characterized by SEM, EDS, XRD, and XPS. The polarization, wettability, and ICR tests were respectively conducted to systemically evaluate the performance of Ni–Co/SS304 in the simulated PEMFC cathode environment. As revealed by the results, the Ni–Co/SS304 can maintain its hydrophobicity under hot-water droplets as high as 80 °C and demonstrates higher conductivity than the bare SS304 substrate before and after polarization (0.6 V vs. SCE, 5 h), which is of great significance to improve the surface hydrophobicity and conductivity of bipolar plates.

Highly Efficient Transformation of Tar Model Compounds into Hydrogen by a Ni–Co Alloy Nanocatalyst During Tar Steam Reforming

“…In the Ni 2p spectrum (Figure e), the peak in fresh 6% Ni–4% Co/char at 852.6 and 869.9 eV were ascribed to Ni 0 , which showed that the metallic Ni mainly existed in the shape of Ni 0 . The new peaks for Ni 2+ at 862.3 eV were observed on the spent 6% Ni–4% Co/char ( N = 1) because of a small amount of Ni being oxidized to NiO, which corresponded to the result of XRD . For the Co 2p spectrum (Figure f), the peaks at 778.0 and 794.2 eV were attributed to Co .…”

“…79 Gai et al and Ren et al both found that the modified char-supported catalysts exhibited higher catalytic activity due to the outstanding graphitized and layered delocalized structures. 46,80 In the Ni 2p spectrum (Figure 6e), the peak in fresh 6% Ni− 4% Co/char at 852.6 and 869.9 eV were ascribed to Ni 0 , 81 which showed that the metallic Ni mainly existed in the shape of Ni 0 . The new peaks for Ni 2+ at 862.3 eV were observed on the spent 6% Ni−4% Co/char (N = 1) because of a small amount of Ni being oxidized to NiO, which corresponded to the result of XRD.…”

“…The new peaks for Ni 2+ at 862.3 eV were observed on the spent 6% Ni−4% Co/char (N = 1) because of a small amount of Ni being oxidized to NiO, which corresponded to the result of XRD. 81 For the Co 2p spectrum (Figure 6f), the peaks at 778.0 and 794.2 eV were attributed to Co. 81 The −0.1 eV of Ni 0 (870 eV) and +0.2 eV of Co 0 (794.0 eV) shift corresponds to the strengthened interaction between Ni and Co due to the formation of Ni−Co alloy, which is ascribed to the difference of the electron work function between Ni and Co. 82,83 The electrons may transfer from Co to Ni, leading to the shifts of the binding energies in the Ni−Co alloy because of a lower electron work function. The electronic conditions of Ni and Co atoms were changed and their electronic properties were improved.…”