Ruddlesden–Popper Sr4Ir3O10 perovskite: A new family for water splitting driven by interlayer oxygen migration

Ruddlesden–Popper (R-P) layered perovskites offer a new possibility for efficient water splitting due to their periodically packed rock-salt and perovskite layers along the c-axis in crystallographic. Herein, a novel R-P Sr4Ir3O10 oxide with a dynamic characteristic of short-range oxygen migration between the SrO rock-salt monolayer and SrIrO3 perovskite multilayers were fabricated. It shows lower Fermi level around the redox potential level of O2/H2O, which enables an interstitial oxygen assisted lattice oxygen evolution mechanism to improve OER performance with low overpotential of 205 and 278 mV at 10 and 100 mA/cm2 in acidic environment. In practical proton exchange membrane (PEM) device, the Sr4Ir3O10 can sustain more than 50 h without obvious decay at 10 mA/cm2, steming from a cascade migration of oxygen species from adsorbed water to interstitial oxygen and then lattice oxygen. This may open a new door to developing high-performance R-P perovskites for application in PEM water electrolysis.