Advancing catalytic plastic waste recycling through multiscale modeling with detailed chemical kinetics

• Applicant: Dr.-Ing. Bjarne Kreitz
• Subject Area: Chemical and Thermal Process Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551119709

The project advances first-principles-based multiscale modeling and automated mechanism generation to develop detailed chemical kinetics for the catalytic upcycling of polyethylene (PE) waste. PE is one of the most produced plastics, but widespread recycling with current techniques is challenging and leads to low-value materials with inferior properties. Thus, it contributes significantly to greenhouse gas emissions and environmentally harmful plastic waste. Catalytic upcycling of PE over bifunctional catalysts via hydrogenolysis to a range of possible products offers a promising solution to establish a profitable circular economy. Potential heterogeneous catalysts were discovered through a trial-and-error approach, but they suffer from a broad product distribution requiring expensive post-processing. We will shift towards a knowledge-driven catalyst design in the project by elucidating the detailed PE hydrogenolysis kinetics over bifunctional catalysts. Automated mechanism generation will be used to identify kinetically relevant pathways from the vast chemical reaction space. A particular focus is to account for the entire catalyst morphology during the automated mechanism exploration, including the metal nanoparticle, the metal oxide support, and metal/metal oxide interfaces. We will design continuously operated hydrogenolysis reactors by incorporating structure-dependent micro-kinetics into first-principles-based multiscale models. Simulations are compared to kinetic experiments conducted over well-defined catalysts to unravel structure-activity relations. The mechanism generation is paired with scaling relations to enable automated high-throughput screening of the complex material space to identify promising materials, which are then experimentally tested. Through an iterative refinement of mechanisms and multiscale models, the project enables an in-silico design of optimally performing bifunctional catalysts and reactors. We will make advances in the fundamentals of multiscale modeling that contribute to closing the material and pressure gap, which tremendously impacts the investigation of all heterogeneously catalyzed reactions.

• DFG Programme: Emmy Noether Independent Junior Research Groups
• Major Instrumentation: GC-MS
• Instrumentation Group: 1700 Massenspektrometer