The present disclosure is directed to an antimicrobial composite material, and more particularly to an antimicrobial composite material comprising particles having a metal or metal alloy core and a porous inorganic material shell, coatings including the antimicrobial composite material, and methods of making the same. In some embodiments, Cu—SiO2 core-shell particles are disclosed in which the Cu core provides antimicrobial activity and the porous SiO2 shell functions as a barrier for the Cu core, thus preventing the Cu core from being directly exposed to air or moisture.