Host-Guest Structure Enabling Electrocatalytic Hydrogen Evolution Performance by POM@TM-BDC Composites.

Developing economical, efficient, and earth-rich electrocatalysts for hydrogen evolution reaction (HER) is quite challenging and ideal. We propose that [P2W18O62]6- as the guest, due to its excellent reversible 18 electron-transfer capacity and redox properties, and then TM-BDC (TM = Ni, Co, Fe, BDC = 1,4-benzene-dicarboxylate) as the host make [P2W18O62]6- packaged and not escape due to its porous structure. Benefiting from strong redox-competent interactions between [P2W18O62]6- and porous structures of TM-BDC and full exposure of abundant active sites, three {P2W18}@TM-BDC composites exhibited excellent HER activity, with {P2W18}@Ni-BDC requiring 198 mV (overpotentials) and 104 mV/dec (Tafel slope) for HER. More importantly, three {P2W18}@TM-BDC composites show excellent stability, with the voltage remaining nearly constant for 24 h. Meanwhile, the linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) curves of three {P2W18}@TM-BDC overlap well with the initial curve after the stability test. Our work offers a promising strategy for synthesizing high-performance electrocatalysts and broadens the scope of nonprecious metal composite material preparation.