Electrochemically Active Nickel Foams as Support Materials for Nanoscopic Platinum Electrocatalysts

Abstract

Platinum is deposited on open-cell nickel foam in low loading amounts via chemical reduction of Pt cations (specifically, Pt(2+) or Pt(4+)) originating from aqueous Pt salt solutions. The resulting Pt-modified nickel foams (Pt/Ni foams) are characterized using complementary electrochemical and materials analysis techniques. These include electron microscopy to examine the morphology of the deposited material, cyclic voltammetry to evaluate the electrochemical surface area of the deposited Pt, and inductively coupled plasma optical emission spectrometry to determine the mass of deposited Pt on the Ni foam substrate. The effect of potential cycling in alkaline media on the electrochemical behavior of the material and the stability of Pt deposit is studied. In the second part of this paper, the Pt/Ni foams are applied as electrode materials for hydrogen evolution, hydrogen reduction, oxygen reduction, and oxygen evolution reactions in an aqueous alkaline electrolyte. The electrocatalytic activity of the electrodes toward these processes is evaluated using linear sweep voltammetry curves and Tafel plots. The results of these studies demonstrate that nickel foams are acceptable support materials for nanoscopic Pt electrocatalysts and that the resulting Pt/Ni foams are excellent electrocatalysts for the hydrogen evolution reaction. An unmodified Ni foam is shown to be a highly active electrode for the oxygen evolution reaction.

On the Temperature Performance of Ethanol Oxidation Reaction at Palladium-Activated Nickel Foam

“…Similarly, a radical modification of electrochemically active surface area for nickel foam was achieved on Pt-modified (via chemically induced reduction) electrode in ref. [33], where this material was comprehensively evaluated with respect to its suitability for a number of electrochemical processes, including hydrogen/oxygen evolution and reduction reactions.…”

The Formation of Surface Oxides on Nickel in Oxalate-Containing Alkaline Media

“…The Ni foam electrodes were weighed analytically prior to the etching pretreatment; the current and charge values are normalized with respect to the mass of the foam. Thus, the specific current density (I s , A g −1 ) and specific charge density (Q s , C g −1 ) are reported, due to the complicated structure of these materials [14,30]. To ensure reproducibility, the experiments carried out with the Ni foam electrodes were replicated five times, each time using a new piece of Ni foam that was pretreated with fresh acid etching solution.…”

“…Open cell nickel foams have been investigated for a variety of electrochemical applications including as electrocatalysts [5], as electrocatalyst support materials [30,[44][45][46], as electrochemical sensors [47], and as electrode support materials in supercapacitors [48,49]. Nickel foams generally display electrochemical characteristics similar to those of bulk Ni with respect to the formation of surface oxides, adhesion with other metals, and electrocatalytic activity.…”

Cathodic Evolution of Hydrogen on Platinum-Modified Nickel Foam Catalyst

“…The circuit includes a constant phase element (CPE) for distributed capacitance; R ct and C dl (as CPE dl ) elements correspond to the HER charge-transfer resistance and double-layer capacitance components, and R sol is solution resistance , correspondingly. Interestingly, analogous HER studies performed on Ptactivated (fully characterized [28]), CVD-produced nickel foam [29,30] and a 3-D porous Ni electrode structure [31] resulted in Tafel slopes on the order of 90 to 159 mV dec −1 and exchange current densities of 3.9 × 10 −4 [30] and 9.5×…”