An adsorbent for carbon dioxide may include a structure that includes composite metal oxide including a first metal (M 1 ) and a second metal (M 2 ) linked through oxygen (O). The first metal (M 1 ) may be selected from an alkali metal, an alkaline-earth metal, and a combination thereof. The second metal (M 2 ) may have a trivalent oxidation number or greater. The composite metal oxide may include mesopores inside or in the surface thereof. The adsorbent may be included in a capture module for carbon dioxide. A method of reducing emissions may include adsorbing carbon dioxide using the adsorbent for carbon dioxide.
