Graphite-shell-chains selectively and efficiently produced from biomass rich in cellulose and chitin.

Graphite-shell-chains have a worm-like nanocarbon configuration with a graphitic structure and mesopores, and they are easily produced from wood by using iron-group metal-catalysed carbonization at 900 °C. The simple production process with natural resources convinced us that this process may occur somewhere on Earth; the product of this process was indeed discovered as biogenic graphite by geochemists. However, the biogenic graphite was 3.7 billion years old, thus occurring long before wood appeared in the world. Here, we investigated appropriate carbon precursors other than wood in various materials and showed that carbon is selectively and efficiently obtained from biomass rich in cellulose and chitin. To enable selective and efficient production from this biomass, it seems the precursors provide a perfect amorphous carbon matrix where metal catalysts can reside at an active size to constantly create a graphite shell during carbonization. The results suggest that graphite-shell-chains could have existed in ancient times. Application developments of this biomass-derived nanocarbon will be useful for sustainable development goals.

Non-Fermi Liquids as Highly Active Oxygen Evolution Reaction Catalysts.

The oxygen evolution reaction (OER) plays a key role in emerging energy conversion technologies such as rechargeable metal-air batteries, and direct solar water splitting. Herein, a remarkably low overpotential of ≈150 mV at 10 mA cm-2disk in alkaline solutions using one of the non-Fermi liquids, Hg2Ru2O7, is reported. Hg2Ru2O7 displays a rapid increase in current density and excellent durability as an OER catalyst. This outstanding catalytic performance is realized through the coexistence of localized d-bands with the metallic state that is unique to non-Fermi liquids. The findings indicate that non-Fermi liquids could greatly improve the design of highly active OER catalysts.