Scalable Production of Monolayer Shell(Pt)@Core(Pd) Nanoparticles by Electroless Cu UPD for Oxygen Reduction Reaction

In this article, we discuss an electroless under potential deposition (UPD) method to synthesize core@shell monolayer nanoparticles in bulk quantities. In this electroless UPD method, potential is controlled and maintained in the UPD region by a redox couple. This electroless path enables the production of core@shell monolayer catalysts on any type of support, unlike the conventional UPD, where potential is controlled by an external power source which allows for the deposition only on conductive supports such as carbon. This was demonstrated by synthesizing Pt(shell)@Pd(core) nanopartricles on both conductive (Vulcan carbon) and non-conductive (alumina) supports by Cu UPD-galvanic replacement method. Core-shell structure of the Pd-Pt nanoparticles was confirmed by STEM characterization. The thickness of Pt shell in Pt@Pd nanoparticles was examined by analytical and experimental observations. Furthermore, catalytic activity of Pt@Pd/C nanoparticles, synthesized by the electroless Cu UPD-galvanic replacement method, was examined for oxygen reduction reaction. Graphical Abstract For monolayer deposition in electroless UPD, OCP of redox couple (R/O) ≥ OCP of bulk deposition of UPD metal