▎ 摘　　要

NOVELTY - Electrode catalyst comprises metal particles supported on a carbon-based carrier; and metal nanoparticles in the form of dendrites are disposed on the surface of the metal particles. USE - The electrode catalyst is useful in carbon dioxide reduction device (claimed) for carbon dioxide reduction. ADVANTAGE - The electrode catalyst has high energy efficiency and current density in a specific voltage range, having porous carbon-based carrier can increase the surface area to improve the current density, thus increasing the carbon dioxide reduction efficiency, having nanoporous structure can increase the carbon dioxide gas mass transfer of the electrode catalyst, and can produce carbon monoxide with high carbon monoxide selectivity and high current density in a system for electrochemically reducing gaseous carbon dioxide by increasing the Faraday efficiency of the carbon monoxide generating reaction. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) carbon dioxide reduction device comprising electrode catalyst; and (2) producing electrode catalyst, comprising obtaining carbon-supported metal particles by drying a first solution including a carbon-based carrier and a first metal precursor dispersed in a first solvent and then heat-treating in a hydrogen atmosphere, and reducing the second solution in which the carbon-supported metal particles, the second metal precursor, and the dispersing agent are dispersed in a second solvent using an acid to grow the metal nanoparticles in the form of dendrites on the surface of the metal particles.