Tuning the product distribution during the catalytic pyrolysis of waste tires: The effect of the nature of metals and the reaction temperature

Metal catalysts based on Ni, Co, and Pd supported SiO2 were evaluated in the catalytic pyrolysis of waste tires using experiments coupled to gas chromatography/mass spectrometry (Py–GC/MS) thermogravimetric analysis with Fourier Transform Infrared spectrometer (TGA–FTIR) techniques. The effect temperature nature metals product distribution reaction pathways was determined. Catalytic promoted aromatization cracking reactions at particularly low temperatures ca. 350 °C, leading mainly formation alkenes (isoprene), aromatic terpenes (p-cymene), aliphatic (d,l-limonene), other compounds such as benzene, toluene, xylenes (BTX). Pd/SiO2 catalyst most selective toward (around 40 %), owing its well-known hydrogenation/dehydrogenation capacity, while CC bond cleavage reactions, alkenes, more favored Ni/SiO2 Co/SiO2 catalysts. In all cases, high selectivity limonene isoprene observed temperature. Above 400 no significant differences between catalyzed uncatalyzed pyrolysis. Herein, high-value hydrocarbons (i.e., d,l-limonene, isoprene, BTX, p-cymene) during tuned by transition Pd) (e.g., <400 °C). results demonstrate that use these is a promising strategy valorize into added-value products.