Electronic Structure Modulation Induced by Asymmetric Cu─Ni Centers in a π-Conjugated Triazine MOF

Designing efficient electrocatalysts for hydrogen generation remains a major challenge because the hydrogen evolution reaction (HER) still relies heavily on platinum (Pt). At the same time, most non-Pt alternatives are limited to single-metal or symmetric bimetallic active sites. Conductive metal–organic frameworks (MOFs) with conjugated ligands are attractive candidates because their redox-active metal nodes can enhance electrocatalytic performance. In this work, we designed and synthesized three H₃TATB-based (2,4,6-tris(4-carboxyphenyl)-s-triazine) MOFs, Cu-MOF, Ni-MOF, and asymmetric bimetallic CuNi-MOF, for HER in alkaline media. Among them, CuNi-MOF exhibited the best performance, requiring only 123 mV overpotential to achieve 10 mA cm⁻² with a Tafel slope of 150 mV dec⁻¹, outperforming Ni-MOF and Cu-MOF. Its enhanced activity is attributed to cooperative interactions between Cu and Ni, which optimize the electronic structure, enhance charge transfer, and accelerate HER kinetics while maintaining stability for 24 h. The triazine-based ligand further stabilizes the active sites and promotes electron transport and hydrogen intermediate adsorption. DFT calculations reveal a narrow bandgap of 0.684 eV and a favorable heteronuclear CuNi configuration that lowers the HER energy barrier. This strategy provides a flexible platform for developing multi-metallic π-conjugated MOFs for alkaline HER.