Bioinspired Dual-Site Photocathode with Atomic Molybdenum and Alkynyl Networks for Scalable Solar Ammonia Synthesis

The Haber–Bosch process, while pivotal for global ammonia production, remains energy-intensive and environmentally unsustainable. Here, we report a nitrogenase-inspired photocathode (Mo 1 /HsGDY@Cu 2 O) that synergistically integrates light-harvesting Cu 2 O nanowires, hydrogen-radical-generating alkynyl-rich graphdiyne (HsGDY), and atomically dispersed molybdenum sites for solar-driven nitrogen fixation. Mimicking the Fe/MoFe-cofactor collaboration in nitrogenase, the photocathode enables efficient N 2 adsorption at Mo 1 sites and hydrogen radical transfer from adjacent alkynyl groups, significantly lowering the energy barrier for N 2 hydrogenation. Under 10-sun illumination, the system achieves a record ammonia yield of 78.9 μg cm –2 h –1 with a Faradaic efficiency of 38.9% while maintaining 86% activity over 240 h. The ammonia solution directly enhances Epipremnum aureum root growth by 2.3-fold, demonstrating immediate agricultural utility. Combined with bias-free operation and scalable solar concentration, this work provides a practical blueprint for decarbonizing fertilizer production. Operando spectroscopy and DFT calculations further reveal that the dual-site synergy─Mo 1 for N 2 activation and alkynyl groups for H • supply─drives the catalytic mechanism, offering a universal strategy for enzyme-inspired energy conversion systems.