Enhancing Water Oxidation of Ru Single Atoms <i>via</i> Oxygen-Coordination Bonding with NiFe Layered Double Hydroxide

Abstract

Designing and synthesizing a highly active single atom catalyst, especially monodispersed noble-metal atoms fixed in two-dimensional layered double hydroxide (LDH) nanostructures, is crucial in accelerating the slow oxygen evolution reaction (OER). Here, Ru single atoms (SAs) are stabilized on NiFe LDH (SARu/NiFe LDH) via an oxygen-coordinated bond after a facile solution reduction procedure. The OER activity evaluation at similar mass loading on glassy carbon reveals that SARu/NiFe LDH shows more activity than pure NiFe LDH in basic media, possessing 99.3% of Faradaic efficiency based on rotating ring-disk electrode measurement. This is mainly due to a strong synergy between Ru SAs and NiFe LDH support. Furthermore, these supported catalysts are developed to an integrative 3D electrode in situ of the nickel foam with a higher specific surface area, which needs only an ultralow overpotential of 196 mV at 10 mA cm–2. This is one of the most efficient electrode containing monoatomic components to date. Theoretical calculations suggests that active sites of Ru can facilitate the rearrangement of electrons and optimize the binding energy both SARu/NiFe LDH catalyst and intermediates during the OER, thereby improving the intrinsic OER activity. This study provides a general avenue to developing efficiently monoatomic and even multiatomic catalysts in the future.