Hydrogen (H₂) is gaining public attention as one of the candidates for the next-generation of energy. Environmentally friendly H₂ is expected to make a major contribution to sustainable societies.  However, the detection of H₂ gas is important in nuclear power stations, coal mines, and semiconductor manufacturing industry. The presence of H₂ can be used to indicate a fire in its early state or to detect impending transformer failure in electric power plants. So, to avoid any accident, designing of new class of H₂ gas sensor is important for the society. In past few decades, various materials such as semiconductor, carbon nanomaterials, metal nanoparticles and so on were explored  as sensing materials for the detection of low concentration of H₂ gas at room temperature conditions. Among these, carbon nanomaterials are widely investigated because of they are enormously sensitive to H₂ at room temperature conditions. In recent years, carbon materials are widely investigated because of their extraordinary chemical, electrical and physical properties. In addition, carbon material have potential application in gas sensor technology.