Atomic Layered IR Constructed Ultrasmall Pdir Core-Shell Nanoparticles as Robust Water Splitting Electrocatalyst in Acid

Abstract

The realization of commercialization of proton electrolyte membrane water splitting (PEMWS) significantly depends on the anodic electrocatalyst working at high potential and strong acidic condition requiring superior oxygen evolution reaction (OER) activity and stability. In this manuscript, we devise the construction of ultrasmall Pd@Ir core-shell nanoparticles (3 nm) with atom layer Ir (3 atomic layers) on carbon nanotubes (Pd@Ir/CNT) as exceptional bifunctional electrocatalyst in acidic water splitting. Due to the core-shell structure, strain generated at heterointerfaces leads to an upshifted d band center of Ir atoms contributing to a 123-fold better mass activity at 1.63 V vs. RHE than commercial IrO 2 ; besides, the electronic hybridization suppresses the electrochemical dissolution of Ir; as a result, a robust stability is also achieved. In hydrogen evolution reaction (HER) catalysis, Pd@Ir/CNT also exhibits a 7.4-time higher mass activity than Pt/C. Furthermore, only 1.7 V is needed to reach water splitting current density of 100 mA cm -2 , 251 mV lower than Pt/C-IrO 2 indicating its exceptionality in acidic water splitting.

Keywords: Proton electrolyte membrane water splitting, Core-shell structure, oxygen evolution reaction, Hydrogen evolution reaction