Leveraging high entropy alloy catalysis for lignin valorization

Within the context of biomass, industries like pulp & paper and biorefineries in 2024 produced around 70 MT/year of a by-product called lignin. Lignin is an abundant green renewable source of aromatic chemicals which can be used to make bio-based polymers, pharmaceuticals and other chemical building blocks. However, 98% of this is burned for use as fuel currently. This project focuses on the use of innovative materials namely "high-entropy alloy (HEA) catalysts" to upcycle these industrial lignin streams to high value chemicals. These catalysts comprise of five or more metals, synthesized by a chemical alloying method followed by subsequent drying, calcination and reduction. Novel HEA catalysts with different compositions were synthesized and their performance in a batch reactor was analyzed. Results showed that precious metals like Pd, Ru or Pt are not required to yield high activity in the reductive catalytic depolymerization. The HEA formulation of Fe,Cu,Ni,Co,Al showed a 12.1 activity gain % over the benchmark catalyst – bimetallic PdCu in literature. In addition, various synthesis parameters were varied with a reduction temperature of 600°C showing best results.