Public defence in Chemical Engineering, M. Sc. Mingze Yang

Title of the thesis: Lignin-derived compounds valorization on metal-free carbon catalysts

Thesis defender: Mingze Yang
Opponent: Prof. Dmitry Murzin, Åbo Akademi University, Finland
Custos: Prof. Ville Alopaeus, Aalto University School of Chemical Engineering

Biomass is a promising alternative to fossil fuels, offering solutions to rising energy demands while supporting carbon neutrality. Among the major components of biomass, lignin is abundant but remains underutilized, making its efficient valorization a critical area of research. Conventional methods, such as oxidative dehydrogenation (ODH) and alkylation-hydrodeoxygenation, often rely on toxic reagents or noble metal catalysts, raising environmental and economic concerns. Therefore, sustainable and metal-free approaches are urgently needed—carbon catalysts present a compelling eco-friendly alternative.

This thesis explores lignin valorization pathways using carbon-based catalysts, focusing on their mechanisms and comparing their performance with traditional metal-based systems. The valorization targets two major categories of high-value products: fine chemicals and biofuels, both of which are essential for advancing sustainability. Experimental results demonstrated the good recyclability and broad applicability of carbon catalysts in the ODH route for producing biaryl and diaryl amine compounds. Additionally, potential strategies for modifying carbon catalysts to enhance alkylation performance were proposed. These findings contribute to expanding the industrial application of carbon catalysts and offer greener routes for lignin valorization.

Keywords: lignin, carbocatalysis, oxidative dehydrogenation, alkylation, solid acid catalyst

Thesis available for public display 10 days prior to the defence at Aaltodoc.