Scalable synthesis of 2D hydrogen-substituted graphdiyne on Zn substrate for high-yield N₂ fixation

Hydrogen-substituted graphdiyne (HsGDY), as a new rising star of carbon materials family, demonstrates high conjugation, robust chemical stability, and versatility for modification. However, grand challenges, including low production rate, disordered topology, and amorphous structure, greatly hinder its large-scale applications. Herein, we report, for the first time, the scalable synthesis (up to gram-level) of two-dimensional (2D) crystalline HsGDY nanosheets with Zn as a substrate. Moreover, as a metal-free catalyst for electrochemical N₂ fixation, 2D HsGDY achieves an ultrahigh yield of 103 μg h⁻¹ mg⁻¹_cat. with a potential of −0.2 V vs reversible hydrogen electrode (RHE), which is comparable with that of noble metals and single-atom catalysts. Different from the heteroatom active sites in carbon-based catalysts reported before, the inner alkynyl C itself in 2D HsGDY was identified as the active site, which adsorbs and activates N≡N due to the positive charge and high spin density triggered by the slight O doping in the form of C=O at the outer alkynyl C. We believe that this Zn-templated scalable production of high-quality HsGDY paves the way for its large-scale production and provides a new playground for the multiple research fields.