Hydrogen Production\nPromotion from Nonrecyclable Plastic\nWaste via a Single-Step Catalytic Thermal Cracking/Steam Reforming\nScheme

A complete analysis of a catalytic pyrolysis scheme,\nevolved to\na combined in situ thermal cracking/steam reforming scheme, to valorize\nnonrecyclable plastic waste is presented. The study aims to analyze\nthe three fractions obtained, focusing on the production of a hydrogen-rich\ngaseous fraction with industrial interest. The optimization in terms\nof hydrogen generation is carried out using various ruthenium-containing\ncatalytic systems prepared by a facile preparation method. Several\ncatalytic systems were tested, all ruthenium-containing materials\ninteracting with g-C<sub>3</sub>N<sub>4</sub>, ZSM5, high-surface-area\ncarbon, and TiO<sub>2</sub> as active supports. In the combined reaction\nscheme defined by catalytic cracking/steam reforming reactions at\n550 °C of the pyrolysis gases using a RuO<sub>2</sub>/TiO<sub>2</sub> composite system in a one-step reaction system, 270.7 mmol\nof hydrogen (13.5 mmol g<sup>–1</sup> of plastic waste) were\nobtained, representing an increase of 227.6 mmol in comparison with\nthe traditional thermochemical process. The contribution is completed\nwith a characterization scheme of the obtained product fractions and\ncomposite catalysts, including a postreaction analysis, which allowed\nthe identification of the main properties (catalysts) and operating\nconditions (setup) to optimize the process.