(617gr) Au@MxOy Core-Shell Nanoparticles As Catalysts for the Oxygen Evolution Reaction
Recently, Au has been found to have beneficial effects on the activity of transition metal catalysts for the OER. Firstly, Au can alter catalyst electronic structure and allow access to higher activity metal oxide phases as was observed for the Au/Mn-oxide system. Additionally, it has been postulated that Au can reduce overpotential requirements for Mn and Co oxides by participating directly in the OER mechanism. In a recent report, Au was also found to enhance the activity of NiCe based catalysts. Lastly, as a high conductivity support, Au can increase the conductivity of insulating metal oxide materials whose high intrinsic activity is thwarted by poor electronic properties. Capitalizing on these beneficial effects, the Au-core metal oxide-shell nanoparticle structure has the potential to achieve enhanced activity in a device-ready form. This nanostructure also provides an increased number of active sites and greater material utilization than thin films and can achieve higher metal loadings without hitting conductivity limitations.
Herein we present the synthesis, characterization and electrochemical performance of Au-core metal oxide-shell (Au@MxOy) nanoparticles as OER electrocatalysts. Single metal and alloy oxide nanoparticles with and without Au cores were synthesized with high uniformity via wet chemical methods. Particle morphology and composition were analyzed using transmission electron microscopy (TEM), scanning TEM energy dispersive spectroscopy (STEM-EDS), scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Electrochemical activity and stability were evaluated in a three electrode rotating disk arrangement in Fe-free conditions for non-Fe based catalysts. The effect of the Au core is evaluated and catalyst performances are compared.
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