Lignification-mimetic dehydrogenative diphenoquinone synthesis and electrochemical CO2 capture

Abstract

Sustainable mitigation of atmospheric CO₂ requires not only efficient capture technologies but also environmentally responsible production of the materials that enable them. Many capture systems rely on materials synthesized via energy-intensive, multi-step processes from non-renewable feedstocks. To create truly sustainable solutions, there is a critical need for green synthetic pathways that minimize the overall carbon footprint of capture technologies from cradle to grave. Here, we report a diphenoquinone-based CO₂ capture material synthesized from the lignin-derived monomer via an enzymatic coupling reaction, establishing a sustainable route under mild, aqueous conditions without complex purification. The reaction selectively forms a crystalline C4–C4′ linked diphenoquinone, confirmed by comprehensive spectroscopic analyses, and avoids the structural heterogeneity typical of lignin-derived products. The resulting molecule exhibits a positive redox potential and robust reversibility, enabling electrochemical CO₂ capture and release with a specific capacity of 1.9 mmol g⁻¹. While initial performance is limited by the physical stability of the reduced species, this work establishes a new paradigm for lignin valorization by transforming renewable phenolics into discrete, functional molecules for CO₂ capture, and offers a broadly applicable platform for green synthesis of bio-derived quinones, providing a foundation for sustainable technologies within a circular carbon economy.