Once the catalyst is introduced in the second stage and steam is fed, hydrogen production and concentration are greatly improved. As observed in Fig. 1, H2 concentration increases from 36.1 vol.% (without catalyst) to 52.1 vol.% (with catalyst) for 20 wt.% of PP in the feedstock. Likewise, H2 production increases from 10.75 to 27.27 mmol H2 g1, respectively. These differences between H2 concentration and H2 production in the catalytic and non-catalytic process suggest that the catalyst promotes water gas shift and steam reforming reactions (Eq (1) and Eq (2)). The increase in the concentration of CO2 and the decrease in CO and light hydrocarbons (C1eC4) confirm that the water gas shift and hydrocarbon decomposition reactions are the main reactions responsible for producing more hydrogen. When the experiments were carried out with a catalyst, synergetic effects take place influencing hydrogen production, resulting mainly from the promotion and the strong ability of Ni to catalyse H2 production [25]. The increase in active H radicals due to plastic addition and the significant role of Ni in the reforming process remarkably improve hydrogen generation in the process.