Physically Adsorbed Metal Ions in Porous Supports as Electrocatalysts for Oxygen Evolution Reaction

Developing highly efficient and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is significantly important for water-splitting. Here, for the first time it is reported that the physically adsorbed metal ions (PAMI) in porous materials can be served as highly efficient OER electrocatalysts, which provides a universal PAMI method to develop electrocatalysts. This PAMI method can be applied to almost all porous supports, including graphene, carbon nanotubes, C3N4, CaCO3, and porous organic polymers and all the systems exhibit excellent OER performance. In particular, the as-synthesized Co0.7Fe0.3CB exhibits a small overpotential of 295 mV and 350 mV at the current density of 10 mA cm(-2) and 100 mA cm(-2), respectively, which exceeds commercial 40 wt% IrO2/CB and most reported non-noble metal-based OER catalysts. Moreover, the mass activity of Co0.7Fe0.3CB reaches 643.4 A g(-1) at the overpotential of 320 mV, which is nearly 4.7 times higher than that of 40 wt% IrO2/CB. In addition, the advanced ex situ and in situ synchrotron X-ray characterizations are carried out to unravel the PAMI synthetic process. In short, this PAMI method will break the conversional understanding, i.e., the most OER catalysts are synthesized chemically, because the new PAMI method does not require any chemical synthesis, which therefore opens a new avenue for the development of OER electrocatalysts.