Catalytic carbon is a type of activated carbon that has been treated to increase its surface area. This treatment makes it more porous and adsorbent than other types of activated carbon. The increased surface area allows catalytic carbon to adsorb more contaminants from water, making it an effective filtration material. Catalytic carbon is made from a variety of materials, including coal, wood, nutshells, and coconuts. The specific material used depends on the intended use of the catalytic carbon. For example, coconut-based catalytic carbon is often used in aquarium filters because it is safe for fish and plants.