Hydrogen Production Promotion from Nonrecyclable Plastic Wastevia a Single-Step Catalytic Thermal Cracking/Steam ReformingScheme

Abstract

A complete analysis of a catalytic pyrolysis scheme, evolved to a combined in situ thermal cracking/steam reforming scheme, to valorize nonrecyclable plastic waste is presented. The study aims to analyze the three fractions obtained, focusing on the production of a hydrogen-rich gaseous fraction with industrial interest. The optimization in terms of hydrogen generation is carried out using various ruthenium-containing catalytic systems prepared by a facile preparation method. Several catalytic systems were tested, all ruthenium-containing materials interacting with g-C3N4, ZSM5, high-surface-area carbon, and TiO2 as active supports. In the combined reaction scheme defined by catalytic cracking/steam reforming reactions at 550 °C of the pyrolysis gases using a RuO2/TiO2 composite system in a one-step reaction system, 270.7 mmol of hydrogen (13.5 mmol g–1 of plastic waste) were obtained, representing an increase of 227.6 mmol in comparison with the traditional thermochemical process. The contribution is completed with a characterization scheme of the obtained product fractions and composite catalysts, including a postreaction analysis, which allowed the identification of the main properties (catalysts) and operating conditions (setup) to optimize the process.