Two new 3D isostructural Co/Ni-MOFs showing four-fold polyrotaxane-like networks: Synthesis, crystal structures and hydrogen evolution reaction

Two new 3D isostructural MOFs, [M(ddbp)0.5(4,4′-biby)0.5(H2O)2](M = Co/Ni, H4ddbp = 1, 3-di (3′,5′-dicarboxylphenyl)benzene, 4,4′-biby = 4,4-bipyridine) with four-fold poly-rotaxane-like networks, have been successfully synthesized and characterized. The hydrogen evolution reaction of two complexes has also been investigated. Notably, Co-MOF has better HER performance with a smaller overpotential of 357 mV at 10 mA·cm−2, lower Tafel slope of 107 mV·dec−1.