Dispersed FeO nanoparticles decorated with CoSiO 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-CoSiO composite consisting of well dispersed iron oxide (FeO) decorated CoSiO hollow nanospheres as an economical and promising OER catalyst. Although CoSiO or FeO alone has little OER activity, their composite exhibits satisfied performance, that is highly related to geometric effect and bimetal component electronic interactions. The Fe-CoSiO composite exhibits comparable catalytic activity to most of transition mental oxide/hydroxide relevant composites at 10 mA cm. It is even 1.6 times higher than commercial RuO electrocatalyst at high current density 100 mA cm in alkaline solution. In this work, surface decoration of transition metal silicate provides a new horizon to design high-performance and economical OER catalysts.