Harnessing solar energy for electrocatalytic biorefinery using lignin-derived photothermal materials

The bio-refinery of lignocellulose exhibits great potential for sustainable development. However, technical barriers for proper utilization of lignin and heavy energy consumption have challenged the profitability and sustainability of such biorefineries. Here, we efficiently converted lignin to photothermal materials (D-Lig-Fe) by the demethylation of lignin and coordinating with Fe3+, producing electricity that could be utilized for the electrocatalytic conversion of 5-hydromethyl-2-furaldehyde (HMF) to 2,5-furandicarboxylic acid (FDCA) when coupled with a thermoelectric generator (TEG) in the bio-refinery. Specifically, D-Lig-Fe exhibited robust and high photothermal efficiency (similar to 36%), producing electricity up to 1.6 V upon natural solar irradiation assisted by a Fresnel lens together with TEG. The as-generated electricity drove a high-yielding conversion of HMF to FDCA via NiCoB catalyst-based electrocatalysis in the bio-refinery. We anticipate that this research will help establish an efficient and practical approach toward an integrated biorefinery.