Support‐Controlled Reaction Pathways via Dynamic Sulfur‐Mediated Interfaces for Selective Urea Electrolysis

ABSTRACT

The development of efficient and sustainable hydrogen production technologies is critical for the transition toward carbon‐neutral energy systems. Coupling the urea oxidation reaction with the hydrogen evolution reaction (HER) offers a low‐energy alternative to conventional water electrolysis, but its practical implementation is limited by poor reaction selectivity and catalyst instability. Here, we report sulfur‐doped graphitized carbon nanofibers (S/GNF) as an adaptive catalyst–support platform enabling dynamic catalyst–support interactions. When combined with Pd and Ni‐based active phases, the system exhibits enhanced catalytic activity, stability, and control over reaction pathways. In particular, the NiS _x /GNF catalyst achieves ∼92% Faradaic efficiency toward N ₂ , significantly exceeding typical values (<40%–50%) reported for Ni‐based systems. In situ Raman spectroscopy and product analysis reveal that sulfur‐induced electronic modulation and enhanced water dissociation promote selective reaction pathways, while sulfur‐mediated in situ reconstruction stabilizes active sites. Integration into a two‐electrode electrolyzer (NiS _x /GNF║Pd–S/GNF) enables hydrogen production at 1.5 V to reach 10 mA/cm ² with 91.7% Faradaic efficiency and excellent durability. Importantly, this work demonstrates that reaction pathways can be governed by dynamic catalyst–support interactions rather than catalyst composition, establishing a new design principle for controlling selectivity in electrocatalysis.