Magnetic Multifunctional Nanostructures as High-efficiency Catalysts for Oxygen Evolution Reactions

Abstract

The search for high-efficiency and environmentally benign water splitting catalysts has been on the rise since this process is a source of renewable, clean energy. However the process is inherently slow, especially for the production of O₂ from H₂O (water oxidation) due to the high electron count and energy intensive bond formation of the reaction. Hence the search for novel catalysts for oxygen evolution reactions (OER) has led researchers to focus on various families of compounds including oxides and recently selenides. Multifunctional nanostructures containing the semiconductor electrocatalyst grafted onto an optically active metallic component might boost the catalytic activity even further due to efficient charge injection. Magnetically active catalysts will also be lucrative since that might induce better adhesion of the oxygenated species at the catalytically active site. In this report we introduce multifunctional, magnetic Au₃Pd–CoSe nanostructures as high-efficiency OER electrocatalysts. These multifunctional nanostructures were synthesized by a chemical vapor deposition (CVD) reaction with cobalt acetylacetonate and elemental selenium on Au-Pd sputter coated silica substrate at 800°C. The morphology of these multifunctional nanostructures were mostly bifunctional Janus-like nanoparticles as seen through scanning and transmission electron microscopy. They also showed soft ferromagnetic behavior. These bifunctional nanoparticles were coated on the anodes of a water oxidation cell and it was observed that these nanoparticles showed a higher OER activity with lower onset potential for O₂ evolution as compared to the conventional oxide-based OER electrocatalysts.