Facile One-Pot Block Copolymer-Mediated Solvothermal Approach for Synthesis of High-Entropy Alloy with Enhanced OER Activity

Herein, we introduce a straightforward synthesis approach for highly active dendritic multimetallic high-entropy alloy (DMHEA@PtIrPdAgRu) nanoparticles with sufficient entropic mixing, featuring uniform distribution of five noble group metals (Pt, Ir, Pd, Ag, and Ru) via a block copolymer-mediated one-pot solvothermal reduction method for oxygen evolution reaction (OER). In this synthesis, <i>N</i>,<i>N</i>-dimethylformamide (DMF) is used as a reductant as well as solvent and core-shell-corona-type (poly-(styrene)-<i>block</i>-poly-(vinylpyridine)-<i>block</i>-poly-(ethylene oxide)) (PS-PVP-PEO) block copolymer as a structure directing agent. The cooperative effect between the copolymer architecture and the reducing environment of DMF promoted a confined nucleation mechanism for forming a single-phase dendritic structure HEA with high compositional uniformity, thereby mitigating phase segregation, a common challenge in the synthesis of multimetallic nanoparticles. This prepared DMHEA@PtIrPdAgRu catalyst exhibits a low overpotential of 490 mV to attain a high current density of 100 mA cm^-2 with a Tafel slope of 442 mV dec^-1 for oxygen evolution. The superior OER performance is attributed to the synergistic cooperation among its active and coordinated metal centers as well as the incorporation of corrosion-resistant metal like platinum.