Coffee Waste Biochar-Supported Copper Electrocatalyst for Biomass Depolymerization: Insights into Surface Dynamics and Catalyst Restructuring
Journal article, 2026
This work introduces a nanostructured copper catalyst supported on biochar derived from spent coffee grounds, designed for the electrochemical depolymerization of lignin in aqueous solutions. Copper nanoparticles were synthesized in situ and subsequently converted via pyrolysis, resulting in copper nanoparticles with a predominantly metallic Cu core and a Cu(I)-enriched surface. Combined XRD, XPS, and STEM analyses revealed copper nanoparticles with a Cu-rich metallic interior and partial surface oxidation to Cu(I). Operando X-ray absorption spectroscopy was employed to probe the Cu(I) surface and assess its stability under the applied potential. Reusability tests demonstrate sustained product selectivity over four catalytic cycles, with only minor structural alterations detected in the fourth run. DFT calculations revealed mixed dispersion and covalent lignin-surface interactions, with arene groups preferentially oriented parallel to the interface at low coverage and perpendicular to the interface at high coverage. This study presents the first nanoscopic copper-based catalyst for lignin depolymerization, providing fundamental insights into the dynamic Cu/Cu2O interface and highlighting its gradual reduction and sustained activity in electrochemical lignin valorization. In contrast to previous studies on bulk Cu electrodes for electrochemical reductive lignin depolymerization, we observe significant surface restructuring of nanoparticles, leading to larger nanostructured copper agglomerates as active electrocatalytic species.
electrocatalysis
densityfunctional theory
nanoparticles
biomass depolymerization
operando XAS
lignin
Author
Lucie M. Lindenbeck
Bergische Universität Wuppertal
Max Planck Inst Kohlenforschung
Franka Stallmann
Bergische Universität Wuppertal
Alvaro de La Fuente Villanueva
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Dirk Lutzenkirchen-Hecht
Bergische Universität Wuppertal
Daniela Ramermann
Max Planck Inst Chem Energy Convers
Marcella Frauscher
AC2T research GmbH
Bjorn B. Beele
Bergische Universität Wuppertal
Anna Rokicinska
Jagiellonian University in Kraków
Piotr Kustrowski
Jagiellonian University in Kraków
Walid Hetaba
Max Planck Inst Chem Energy Convers
Christian W. Lehmann
Max Planck Inst Kohlenforschung
Joakim Halldin Stenlid
Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry
Bruno V. M. Rodrigues
Bergische Universität Wuppertal
Adam Slabon
Bergische Universität Wuppertal
ACS Sustainable Chemistry & Engineering
2168-0485 (eISSN)
Vol. 14 11 5411-5424Subject Categories (SSIF 2025)
Materials Chemistry
Organic Chemistry
Areas of Advance
Materials Science
DOI
10.1021/acssuschemeng.5c11807