▎ 摘　　要

NOVELTY - Structure comprises conductive carbon nanotube structure; and iron oxide bonded to the surface of the carbon nanotube structure. USE - The structure is useful for producing high-purity methane. ADVANTAGE - The structure reduces concentration of hydrogen sulfide, improves methane production rate in anaerobic digestion process through direct electron transfer between acid-producing microorganism and methanogenic microorganism, can lower hydrogen sulfide concentration in biogas through sulfur adsorption, and generates high-purity methane using only conductive carbon nanotube structure to which iron oxide is bonded without additional equipment. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for producing structure, comprising (a) manufacturing a conductive carbon nanotube structure; and (b) bonding iron oxide to the surface of the carbon nanotube structure.