Dispersed FeO_x nanoparticles decorated with Co₂SiO₄ hollow spheres for enhanced oxygen evolution reaction

Oxygen evolution reaction (OER) has drawn ever-increasing attention because of its essential role in various renewable-energy technologies. In spite of tremendous research efforts, developing high-performance OER catalysts at low cost remains a great challenge. Inspired by two earth-abundant elements Fe and Si, herein, we report a Fe-Co₂SiO₄ composite consisting of well dispersed iron oxide (FeO_x) decorated Co₂SiO₄ hollow nanospheres as an economical and promising OER catalyst. Although Co₂SiO₄ or FeO_x alone has little OER activity, their composite exhibits satisfied performance, that is highly related to geometric effect and bimetal component electronic interactions. The Fe-Co₂SiO₄ composite exhibits comparable catalytic activity to most of transition mental oxide/hydroxide relevant composites at 10 mA cm^-2. It is even 1.6 times higher than commercial RuO₂ electrocatalyst at high current density 100 mA cm^-2 in alkaline solution. In this work, surface decoration of transition metal silicate provides a new horizon to design high-performance and economical OER catalysts.