Electrochemical Upcycling of Biomass into Functional Materials for Water Remediation Coupled with Energy-Saving Hydrogen Production

The sluggish kinetics of the anodic oxygen evolution reaction (OER) poses a major barrier to energy-efficient hydrogen production from water electrolysis. Herein, we report a synergistic biochar-assisted water electrolysis (BAWE) system that replaces OER with the thermodynamically favorable biochar oxidation reaction (BOR) on a NiFe layered double hydroxide nanosheet anode (NiFe LDH/NF). The NiFe LDH/NF exhibits a low potential of 1.5 V vs RHE to deliver 100 mA cm–2, boosting hydrogen production by 62% compared to conventional water electrolysis with a low energy consumption of 3.31 kWh Nm–3 H2. The electrooxidation process upcycles the biochar into a functionalized adsorbent with hierarchical porosity and enriched oxygen-containing groups, achieving 97.42% phenol removal. Density functional theory (DFT) calculations confirm that chemical functionalization dominates the adsorption enhancement, with pore restructuring playing a supportive role. This work establishes a sustainable dual-pathway route for energy-saving hydrogen production coupled with the conversion of biomass waste into high-value functional materials for environmental remediation.