Production of hydrogen and carbon nanotubes via catalytic thermo‐chemical conversion of plastic waste: review

Abstract BACKGROUND Plastic waste has been growing at an alarming rate with dissatisfactory recycling rates. It has a potential to be used for the recovery of hydrogen and carbon nanotubes due to its intrinsic properties. RESULTS Thermo‐chemical processes may be used to tap into the recovery of these resources from the wastes. Catalysts can be employed to increase the gaseous yield and to optimize the process parameters. Hydrogen production is greatly influenced by the catalyst properties, temperature, steam and feedstock. Similarly, the carbon deposits formed are influenced by many factors such as type of metal catalyst used and metal–support interaction. This review focuses on studies employing catalytic thermo‐chemical processes for extracting hydrogen and carbon nano structures from plastic wastes while evaluating the role of parameters such as temperature, catalyst type, catalyst composition, steam/feed ratio, feed rate, feedstock and their effect on the product yields. CONCLUSION In view of increasing concerns regarding waste management, climate change and energy security the possibility of employing waste products for producing clean energy in a sustainable manner is appealing and needs additional fundamental research. © 2019 Society of Chemical Industry