Plastic pyrolysis technology, as an effi cient and stable path for chemical recycling of waste plastics, alleviates current energy

pressures and solves the problem of continuous accumulation of waste plastics in the environment. At present, the vast

majority of research on plastic pyrolysis is focused on how to improve the yield and quality of liquid fuels, while there is

generally little research on the gases generated by plastic pyrolysis. However, gases such as H 2 , CH 4, and light hydrocarbons

generated during pyrolysis also have high utilization value, and have very considerable application prospects in chemical,

aerospace, and metallurgical fi elds. In addition, compared with the separation diffi culties of liquid products, the treatment

of gas products is easier and more conducive to subsequent utilization. This article discusses and analyzes the yield and

composition of gases generated by plastic in three diff erent pyrolysis methods: direct pyrolysis, catalytic pyrolysis, and

microwave pyrolysis. Compared to traditional direct pyrolysis, catalytic pyrolysis and microwave pyrolysis can treat plastic

waste more effi ciently and energy-effi cient, and have higher gas yields. This article also discusses various factors such as

temperature that infl uence the formation of gas products and their importance. Finally, the challenges faced are proposed,

aiming to provide reference and direction for future research on improving the yield of gas generated by plastic pyrolysis.