In order to overcome the performance limit of OER catalysts imposed by the scaling relationship, catalysts that operate by unconventional mechanisms need to be developed. Through DFT-based computational analysis, Rossmeisl and co-workers proposed that introducing proton acceptor-donor sites might lead to a bifunctional pathway for O-O bond formation, thereby circumventing the volcano limit in the OER . Analogous bifunctional mechanisms have been reported for highly active catalysts in ammonium synthesis from nitrogen and methanol synthesis from CO2 . For the OER, however, there is yet no experimental report of non-precious bifunctional catalysts that outperform the best conventional catalysts. Here, we describe a new OER catalyst that significantly surpasses the current performance limit of all known metal oxides in alkaline solutions, including the current state-of-the-art NiFeOx catalyst. This catalyst is stable and can be easily prepared from nickel foam (NF), a readily available and commonly used substrate in OER. Operando X-ray absorption spectroscopy reveals the unique structure of this catalyst consisting of nanoclusters of -FeOOH covalently linked to the edge sites of a -NiOOH support, which is formed in situ on NF. DFT computations suggest that this structure allows for a bifunctional mechanism facilitating the O-O bond formation, leading to exceptional catalytic activity.