Polymeric waste valorization at a crossroads: ten ways to bridge the research on model and complex/real feedstock

Abstract

The valorization of polymeric wastes, such as biomass, tires, and plastics, via thermal depolymerization (i.e., pyrolysis or liquefaction) and simultaneous or subsequent catalytic treatment has gained enormous momentum. The inherent hurdles when using complex polymeric wastes or their products as feedstock have led researchers to conclude that obtaining a fundamental kinetic understanding of the catalytic stage is unfeasible. To overcome the issues related to feedstock complexity, the majority of researchers have decided to use representative model compounds or probe molecules (i.e., surrogates). Two separate mainstreams have emerged in this field: one focusing on the fundamental kinetic understanding of model molecules and the other focused on studying real feedstock. We aimed to merge these approaches to utilize and acknowledge their potential and drawbacks. Therefore, herein, we provide ten recommendations for exploiting the existing synergies between the two approaches. This manuscript first contextualizes our proposed recommendations with a short overview on the thermocatalytic valorization field for polymeric waste, the complex compositions of reactants and products, the progress made in the individual fields of model and real feedstock, comparisons of both feedstock types, and some previous history on hydrocarbon conversion. Subsequently, we present guidelines for a truly cooperative and synergetic research effort.