Tan Zhang, Zhikai Che, Yuru Song, Rui Yao, Jinping Li, Yuhan Sun, Guang Liu
The electrocatalytic nitrogen reduction reaction (NRR), offering an attractive route to ammonia (NH 3 ) from dinitrogen (N 2 ) and water, has attracted substantial interest. However, conventional hydrophobic modification strategies face comprehensive challenges: effectively inhibiting the competing hydrogen evolution reaction (HER) inevitably impedes the critical proton-coupled electron transfer (PCET) steps essential for efficient NRR. Herein, we present a high-performance electrocatalyst based on alkanethiol-modified iron hollow fibers (Fe HF-C x, x = 6, 12, and 18). Significantly, the optimized Fe HF-C12 achieves water management at the interface, suppressing HER without hindering the dynamic water activity essential for proton supply during NRR. Compared to the unmodified Fe HF (3.5%, 27.1 μg h –1 cm –2 ), this distinctive interfacial design achieves a significantly improved Faradaic efficiency of 18.8% and a higher NH 3 yield rate of 40.0 μg h –1 cm –2 . Multitechnique characterizations and simulations unveil the triple synergistic function of the alkanethiol layer: (i) N 2 enrichment at the electrode–electrolyte interface, (ii) selective suppression of HER without impeding dynamic water activity for PCET, and (iii) corrosion inhibition via robust thiolate-Fe bonding.