Metal-free carbons have recently shown great efficiency in several catalytic processes, including oxidative dehydrogenation (ODH) of ethylbenzene and alkenes, hydrogen evolution, liquid Bronsted and Lewis acid catalysis and electrochemical reactions. The catalytic activities of carbon materials are intimately related to their defects, structures, and surface chemistry. In particular, nitrogen functionalized carbons present different surface functional groups, and they can be used as multifunctional catalysts, either through their electronic or nucleophilic properties, or their ability to form additional H bonds with substrates. This book provides an overview of the preparation, characterization and application of metal-free functionalized carbons, including carbon nanotubes, graphene, carbon nitride and covalent organic frameworks (COFs). It is ideal for researchers and industrialists working in catalysis, gas sensing and carbon dioxide storage.