Fabrication of Coral-like Pd based Porous MnO₂ Nanosheet Arrays on Nickel Foam for Methanol Electrooxidation

Abstract

Direct methanol fuel cells (DMFCs) have been seen as one of the desirable power sources, and the performance always depends on the ability of electrode materials to oxidize methanol. In this work, we report a novel electrode composed of coral-like Pd and porous MnO 2 nanosheet arrays on nickel foam (Pd−MnO 2 /NF). MnO 2 and Pd are successively electrodeposited on NF with different concentrations of PdCl 2 , which decides the shape of Pd and catalytic properties. Compared with Pd/NF, Pd−MnO 2 /NF exhibits excellent catalytic performance and good stability for methanol oxidation in alkaline solution. The mass activity of Pd−MnO 2 /NF with low Pd loading is 197.7 mA mg −1 , which is 2.3-fold higher than that of Pd/NF. The improvement of performance mainly comes from MnO 2 , which supplies a number of oxygen atoms to reduce intermediates and enhance antipoisoning ability.

Fabrication of Composite Material with Pd Nanoparticles and Graphene on Nickel Foam for Its Excellent Electrocatalytic Performance

“…In Fig. 7d, the two main peaks of binding energy of Ni 2p 3/2 and Ni 2p 1/2 at 855.7 eV and 873.3 eV with two satellite peaks, respectively, which revealed the oxidation state of Ni 2+ [40]. Compared with Fig.…”

“…Additionally, the Pd/rGO/PDA@NF did not have obvious catalytic activity when the concentration of KOH solution was 0.10 mol L −1 . So KOH electrolyte provides conductive effect in ethanol eletrocatalytic oxidation [40]. The catalytic activity of Pd/rGO/PDA@NF enhanced during frequent potential cycling change in the electrolyte with higher concentrations of KOH or ethanol in Figs.…”

Effect of Pd on the Electrocatalytic Activity of Pt towards Oxidation of Ethanol in Alkaline Solutions

“…0.5 V, which is the onset of the EOR, currents in the negative scan direction are higher, which reveals that in the positive scan direction the surface may be blocked by some ethoxy adsorbed species, which have been oxidized at higher potentials. Regarding the evolution of the current densities with the PtPd ratio (Figure 6), PtPd binary catalysts exhibit considerable improvements over pure Pt and Pd [22,53]. In other words, the electrocatalytic activity of Pt nanoparticles improves by the incorporation of Pd on the nanoparticle and reaches a maximum at a Pt:Pd ratio of 60:40.…”

“…Nowadays, the oxidation of alcohols, like ethanol, in alkaline media has gained attention since non-Pt-based catalysts, such as Pd-based catalysts, can be used as the electrocatalyst for the oxidation and reduction reaction [21]. These alternative catalysts may decrease the cost of DEFCs and facilitate their commercialization [22,23]. The prevailing mechanism of the EOR produces acetaldehyde through the cleavage of the C-H bond, which can undergo the aldol condensation reaction in alkaline media.…”

Enhanced Electrocatalytic Activity of Methanol and Ethanol Oxidation in Alkaline Medium at Bimetallic Nanoparticles Electrochemically Decorated Fullerene‐C60 Nanocomposite Electrocatalyst: An Efficient Anode Material for Alcohol Fuel Cell Applications

“…Cheng et al. [23] reported the Pd−MnO 2 /Nickel Foam catalyst for high‐performance electrooxidation of methanol. It exhibited superior catalytic activity, long‐term stability, and anti‐poisoning ability.…”