Improved conductivity of a new Co(II)-MOF by assembled acetylene black for efficient hydrogen evolution reaction

Metal–organic frameworks (MOFs) incorporating different metal nanoparticles or conductive additives are expected to possess desirable catalytic performance. Herein, we report a novel 3D microporous Co(II)-MOF, [Co1.5(TTAB)0.5(4,4′-bipy)(H2O)] (denoted CTGU-9), based on 3,4,5-tricarboxylic-(3′,4′,5′-tricarboxylazophenyl)benzene (H6TTAB) and 4,4′-bipyridine (4,4′-bipy) ligands. To improve electrical conductivity, a series of composites was integrated by the assembly of CTGU-9 and acetylene black (AB), and shows distinct electrocatalytic activity for the hydrogen evolution reaction (HER). Strikingly, the AB&CTGU-9 (3 : 4) composite exhibits superior HER performance with a very favorable onset potential of 98 mV, an overpotential of 128 mV at 10 mA cm−2, a small Tafel slope of 87 mV dec−1 and long-term stability of at least 21 h. These results indicate that the integration of MOFs with conductive cocatalysts could produce an effective candidate electrocatalyst for HER. Additionally, the gas sorption behavior for N2, CO2, and CH4 is also investigated.