Electrocatalytic Activity of Platinum-Nickel Layers Deposited on Nickel Foam for Formic Acid Oxidation in Acidic and Alkaline Media

Abstract

The performance of direct formic acid fuel cells (DFAFCs) is greatly determined by the catalyst materials. Pt nanoparticles-based heterogeneous structures are among the most important substances for the oxidation of formic acid (FAO). In this study, Ni foam catalyst layered with platinum has been investigated as the catalyst for the oxidation of FAO in acidic and alkaline media. The catalyst has been fabricated via a two-step procedure involving the electroless deposition of the Ni layer using sodium hypophosphite as a reducing agent and subsequent electrodeposition of the platinum layer. In this work, Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and X-ray Diffraction have been used to characterize the morphology, structure, and composition of the prepared catalysts. The electrochemical behavior of the bare Pt, Ni/Ni foam, and PtNi/Ni foam electrodes towards the oxidation of formic acid in acidic and alkaline media was evaluated using cyclic voltammetry.It was found that the PtNi/Ni foam catalyst has a significantly higher electrochemically active surface area of Pt equal to ca. 71 cm2 than pure Pt. Moreover, the PtNi/Ni foam catalyst shows an enhanced electrocatalytic activity towards the FAO via direct pathway in both acidic and alkaline medium compared to those of Ni/Ni and pure Pt electrodes. Furthermore, the prepared PtNi/Ni foam catalyst exhibits greater tolerance of CO than the single-metal Pt in acid solution. Concomitantly, the PtNi/Ni foam catalyst is tolerant to CO poisoning n alkaline media demonstrating high poison removal ability. The PtNi/Ni foam catalyst seems to be a promising future anode material for DFAFCs.