Surface anchoring and structural confinement of iron species within wood-derived carbon for efficient electrocatalytic nitrate reduction to ammonia.

Electrocatalytic nitrate reduction reaction (NO3⁻RR) to ammonia presents a sustainable electrochemical strategy for mitigating nitrate pollution while recovering valuable resources. Although upcycling wood-derived carbon into electrocatalysts is a promising bioresource valorization route, its inherently low specific surface area (SSA) and poor intrinsic catalytic activity severely hinder its practical deployment. Herein, we propose a synergistic surface anchoring and structural confinement strategy to construct an electrode (FePAW) for efficient nitrate remediation. Amidoxime groups coordinate Fe3+ on the wood scaffold, while polyvinyl alcohol infiltrated into the wood lumens forms an interconnected carbon network after pyrolysis. This structure improves lumen utilization and increases the SSA to 1178.88 m2 g-1 while suppressing the aggregation of Fe species. Consequently, FePAW delivers an NH3 Faradaic efficiency of 93.28% and an NH3 yield rate of 1.29mmol h-1 cm-2 at - 0.4 V. In situ ATR-FTIR and DFT calculations further indicate that Fe incorporation facilitates NOx-intermediate adsorption and hydrogenation, promoting deep reduction toward NH3. The post-electrolysis solution also shows a favorable preliminary plant-growth response in mung bean cultivation. Furthermore, an aqueous Zn-NO3⁻ battery using FePAW as the cathode delivers a peak power density of 3.1 mW cm-2 for electricity and NH3 co-generation. This work provides an integrated strategy for converting wood biomass into efficient electrodes for nitrate remediation and sustainable nitrogen-resource recovery.