Biomass‐Coupled HER System: A Strategy for Sustainable and Low‐Cost Hydrogen Production

ABSTRACT Biomass‐based hydrogen production offers a sustainable and carbon‐neutral pathway for addressing the growing demand for clean energy. However, conventional biomass‐to‐hydrogen technologies such as pyrolysis and gasification suffer from high energy consumption, harsh operational conditions, and low hydrogen purity, hindering large‐scale deployment. Here, we present a biomass‐assisted water electrolysis strategy utilizing pine‐derived carbon anodes with hierarchical structures and abundant C─H active sites. These structural features enable rapid OH⁻ transport and enhance carbon oxidation reaction kinetics under high current densities. Specifically, as prepared PA‐10 sample delivers at only 1.2 V vs. reversible hydrogen electrode, outperforming conventional oxygen evolution reaction catalysts such as RuO ₂ . Mechanistic insights from in situ characterizations and density functional theory calculations confirm that C─H sites act as thermodynamically favorable precursors for carbon radicals, which trigger the generation of reactive oxygen intermediates (ROIs) and stabilize the binding of ROIs to the carbon surface. We further constructed a membrane‐free flow electrolyzer, achieving a low levelized cost of hydrogen at 1.56 USD/kg when powered by renewable electricity. This strategy significantly advances biomass‐assisted electrolysis as a scalable, low‐cost, and sustainable hydrogen production technology.