Synergetic Metals on Carbocatalyst Shungite.

The naturally occurring Palaeoproterozoic carbon mineral shungite is a complex raw carbon microporous matrix, loaded with a wide range of elements. Shungite exhibits a disordered and amorphous structure with highly irregular building blocks. Shungite incorporates metals in its structure; typically catalytic elements such Fe and Ni are present, as well as the toxic elements Pb and As at mg g-1 levels. We show here that incorporation of the metals in the carbon matrix of shungite leads into synergistic catalytic effect. We investigate the application of shungite in energy related electrochemical catalytic reactions, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). All elements have a synergetic effect, thus contributing for shungite's interesting catalytic performance towards a different range of electrochemical reactions, outperforming other tested carbon allotropes, such as carbon black, metal loaded carbon nanotubes, fullerene, and glassy carbon. These findings have profound impact on the application of the natural carbon materials for catalysis.