Abstract
Metal nanoclusters (NCs, size < 2 nm) are emerging materials in catalysis owing to their unique catalytic and electronic properties such as high surface/volume ratio, high redox potential, plethora of surface active sites, and dynamic behavior on a suitable support during catalysis. Herein, in situ growth of ultrasmall and robust Co@beta-Co(OH)(2) NCs (approximate to 2 nm) hosted in a honeycomb-like 3D N-enriched carbon network was developed for water-oxidation catalysis with extremely small onset potential (1.44 V). Overpotentials of 220 and 270 mV were required to achieve a current density of 10 mAcm(-2) and 100 mAcm(-2), respectively, in alkaline medium (1m KOH). More promisingly, at eta(10)= 240 mV, the prolonged oxygen evolution process (> 130 h) with faradaic efficiency > 95% at a reaction rate of 22 s(-1) at 1.46 V further substantiated the key role of the ultrasmall supported NCs, which outperformed the benchmark electrocatalysts (RuO2/IrO2) and NCs reported so far. It is anticipated that the high redox potential of NCs with regeneratable active sites and their concerted synergistic effects with the Nenriched porous/flexible carbon network are inherently worth considering to enhance the mass/charge transport owing to the nanoscale interfacial collaboration across the electrode/ electrolyte boundary, thereby efficiently energizing the sluggish/challenging oxygen evolution process.