▎ 摘　　要

NOVELTY - Composite structure comprises cellulose-derived carbon layer and a metal layer present on the cellulose-derived carbon layer. The metal layer includes metal nanoparticles. The cellulose-derived carbon layer comprises a carbon nanocluster having an aromatic ring. USE - Used as composite structure. ADVANTAGE - The method can rapidly manufacture metal nanoparticles of very small size that are uniformly formed at high density regardless of the type of metal. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for manufacturing composite structure, comprising (i) manufacturing a structure including a conductive carbon layer and a cellulose layer present on the conductive carbon layer, (ii) preparing a solution containing a metal precursor, (iii) applying the solution prepared in the second step on the cellulose layer of the structure prepared in the first step to prepare a structure comprising a conductive carbon layer, a cellulose layer, and a layer of a metal precursor solution in the above order, and applying a current to the conductive carbon layer side of the structure, and (iv) forming carbon nanoclusters having aromatic rings in the cellulose layer by Joule heat generated from the side of the conductive carbon layer and inducing reduction of the metal precursor.