"Blood charcoal" obtained by sprinkling animal blood on charcoal and firing it has been used as a bleaching agent in Japan for a long time. I also have.Even today, carbon materials introduced with heteroatoms (heteroatom-doped carbons) are known to be able to catalyze various electrochemical reactions, and are expected to be applied as electrode catalysts for batteries.

　On the other hand, ascidians, which are a specialty of the Tohoku Sanriku region, are the only animals that can produce cellulose, and it is known that cellulose nanofibers (CNF) accumulated in ascidian shells become high-quality carbon when carbonized.Furthermore, since the dried blood meal obtained by drying the waste blood from the livestock industry contains a large amount of elements such as hem iron, nitrogen, and phosphorus, in this research, industrial waste is achieved by mixing and firing these. I thought that it might be possible to synthesize heteroelement-doped carbon by utilizing the material.

　In fact, when CNF derived from sea squirt shells and dried blood meal were mixed and fired, a "nano blood coal" was formed in which a nano-sized carbon structure and various hetero elements such as iron, nitrogen, and phosphorus were combined.It has been clarified that this "nano-blood coal" is an amphoteric electrode catalyst having high activity in both oxygen reduction reaction and oxygen evolution reaction, and has performance comparable to an electrode catalyst using rare metals such as platinum carbon catalyst. It is said that it was.

　The results of this research have the potential to utilize industrial waste, which had been difficult to dispose of, in the manufacture of next-generation energy devices, and are expected to become a technology that promotes resource circulation and energy circulation and contributes to the promotion of SDGs. Will be done.

Paper information:[Science and Technology of Advanced Materials] Bifunctional rare metal-free electrocatalysts synthesized entirely from biomass resources