Effect of electron transfer of 2D Ti3C2Tx@MOF heterostructure on hydrogen evolution reaction activity

Metal-organic framework (MOF) layers were grown in situ from 2D transition metal carbides (MXenes, Ti 3 C 2 T x ) at room temperature to obtain the two-dimensional (2D) Ti 3 C 2 T x @MOF heterostructures with a tightly connected interface. This interface provided more titanium atoms in the low-valence state in comparison to the original Ti 3 C 2 T x , thus facilitating more electron transfer from Ti 3 C 2 T x to MOF-(Fe/Co) nanosheets . The charge density difference and density functional theory results disclosed that Ti 3 C 2 T x could modulate the electronic density around the active sites and lower ΔG H * energy barrier of 2D MOF-(Fe/Co) nanosheets towards the improved hydrogen evolution reaction (HER) activity. The obtained 2D Ti 3 C 2 T x @MOF heterostructures exhibited a much higher HER activity in 1 M KOH electrolyte (with the overpotential of 104 mV at 10 mA/cm 2 and Tafel slope of 79 mV/dec) than those of 2D Ti 3 C 2 T x @MOF-TH, 2D MOF nanosheets , and Ti 3 C 2 T x nanosheets. This research provides a basis for developing superior 2D MOFs, which can enhance HER properties through efficient electronic transport at the heterojunction interface.