Electrooxidation Of Glycerol On Self-Organized, Mixed Au-Pt Interfaces Formed On Ni Substrates

Glycerol is a biproduct of esterification reactions in biodiesel production. Identifying new uses for the significant oversupply of glycerol can reduce the costs associated with biodiesel production. Glycerol is of interest as the anodic half-reaction paired with cathodic electrolytic reactions such as hydrogen evolution or CO2 reduction. Replacing water oxidation with glycerol oxidation can significantly decrease the overall cell potential for generating the reduced product on the cathode, and thus, improve the power conversion efficiency of the cathodic process. Here, we describe a method for fabricating hierarchically-structured glycerol electrooxidation anodes by galvanic replacement reactions on Ni substrates. We show that galvanic replacement is an effective approach to synthesize mixed Au-Pt electrodes with improved electrochemical durability and lower onset potentials for glycerol oxidation compared to otherwise identical monometallic Pt or Au electrodes, respectively. X-ray photoelectron spectroscopy characterization of the mixed-metal electrodes show that the electronic structure of surface Pt is modified by the presence of Au, which can possibly explain the enhanced electrochemical durability of the mixed-metal electrodes. We also show that the galvanic replacement process can be translated to high surface area Ni foam electrodes for improving the electrochemical durability at higher geometric current densities vs equivalent planar electrodes. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.