Breaking Symmetry of Single-Atom Catalysts Enables Extremely Low Energy Barrier and High Stability for Large-Current-Density Water Splitting

Abstract

The instability and low large-current-density efficiency for a single atomic metal species system have aroused widespread concern. Herein, the Ru single-atom system constructed on iron–cobalt layered double hydroxide (Rux SACs@FeCo-LDH) exhibits extremely low oxygen evolution reaction (OER) overpotentials of 194 and 246 mV at current densities of 10 and 1000 mA cm− 2, respectively, and high stability beyond 1000 h at 1000 mA cm− 2, far surpassing commercial RuO2. Moreover, its mass activity is ∼2 and 6 times higher than that of Ru and FeCo-LDH, respectively. Extraordinarily, it only needs 1.52 V to achieve 1000 mA cm− 2 current densities for water-splitting, and is almost unchanged after 1000 h, as the highest performance reported so far. Experimental and theoretical calculation results evidence that, partial substitution of oxophilic-Ru atoms to FeCo-LDH triggers the reconstruction at symmetry breaking interfaces, promoting O-O coupling at Ru-O active sites for OER, beneficial for suppressing multiple heteroatomic interface instability under large-current-density water-splitting. Our strategy opens up opportunities for lifting single-atom stability in industrial-scale hydrogen production from water-splitting.

Recent Advances of Modified Ni (Co, Fe)-based LDH 2D Materials for Water Splitting

“…In the most studies, metal hydroxides are inevitable during OER and HER, which are also widely regarded as highly active catalytic sites with superior activity of current density. Ni (Co, Fe)-based LDH materials featured by 2D morphology are the most typical hydroxides as HER and OER catalysts with high performance, rich sources in earth and convenient preparation methods, which have grown into a category of non-precious metal-based electrocatalysts for substituting precious metal materials [12,22,23]. Nowadays, with the advantages of high current density (reaching up to 1000 mA cm -2 ) and superior stability (1000 hours), the Ni (Co, Fe)based LDH materials exhibit a promising potential of substitution for commercial precious metal-based materials, and also have achieved more attention in water splitting technology.…”