Embedding tetrahedral 3d transition metal TM₄ clusters into the cavity of two-dimensional graphdiyne to construct...

On the basis of density functional theory (DFT) calculations, we have systematically investigated the structures and hydrogen evolution reaction (HER) catalytic activities for a series of new composite systems TM₄@GDY (TM = Sc, Ti, Mn, Fe, Co, Ni and Cu), which are constructed by embedding tetrahedral 3d transition metal TM₄ clusters in the in-plane cavity of two-dimensional (2D) π-conjugated graphdiyne (GDY). Our computed results reveal that compared with the constituent subunits, namely the sole TM₄ cluster and GDY, all these composite TM₄@GDY nanostructures can uniformly exhibit considerably high HER catalytic activity over a wide range of hydrogen coverage, and especially the Fe₄@GDY and Co₄@GDY systems can possess higher HER activity, in view of their higher number of active sites. The high HER catalytic activity for TM₄@GDY can be mainly due to the occurrence of obvious electron transfer from TM₄ cluster to GDY, significantly activating the correlative C and TM atoms. Moreover, all these composite TM₄@GDY systems can also exhibit high structural stability and good conductivity. Therefore, all of them can be considered as a new kind of promising HER catalyst, and this study can provide new strategies for designing low-cost and high-performance 2D carbon-based electrocatalysts.