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 (Mo1/HsGDY@Cu2O) that synergistically integrates light-harvesting Cu2O 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 N2 adsorption at Mo1 sites and hydrogen radical transfer from adjacent alkynyl groups, significantly lowering the energy barrier for N2 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─Mo1 for N2 activation and alkynyl groups for H• supply─drives the catalytic mechanism, offering a universal strategy for enzyme-inspired energy conversion systems.