Y.G. Li, Y. Wang, J.M. Lua, B. Yang, X.Y. San, Z.-S. Wu*

Nano Energy, 2020, 78, 105185.

DOI: 10.1016/j.nanoen.2020.105185 [PDF]

Exploring highly active and stable oxygen evolving electrocatalysts is the key for electrochemical water splitting and renewable chemical conversion. RuO₂is one of the benchmark oxygen evolving electrocatalysts, but remains challenging in high activity in all-pH electrolytes. Herein, we report a confined oxygenation strategy using the finite oxygen species from graphene oxide to synthesize two dimensional (2D) heterostructures of intrinsically defective RuO₂nanocrystals uniformly grown on graphene (2D D-RuO₂/G), showing ultrathin thickness of 9 nm, high specific surface area of 125 m²g⁻¹, enriched hydroxylated surface and notably intrinsic defective RuO₂with low Ru–O coordination number of 5. Consequently, 2D D-RuO₂/G exhibits a robust stability and an extraordinary oxygen evolution reaction (OER) performance both in acidic and alkaline solutions, achieving a current density of 10 mA cm⁻²at the overpotential of 169 and 175 mV, and a water oxidation turn over frequency of 1.07 and 1.25 S⁻¹at 270 mV, respectively, corresponding to 344 mV of total overpotential at 10 mA cm⁻²in acidic and alkaline electrolytes, which greatly exceeds the state-of-the-art of pH-universal OER electrocatalysts. Theoretical studies indicate that intrinsic defective Ru sites can enhance the adsorption and accelerate the decomposition of hydroxyl groups to boost the OER activity. This confined oxygenation strategy provides the opportunities to construct 2D advanced defective OER electrocatalysts in all-pH electrolytes.