Ultrathin 2D-Pt/NiFe-LDH/2D-Pt Sandwiched Catalyst toward Synergistically Enhanced Electrocatalytic Hydrogen Evolution Reaction

The search for efficient Pt electrocatalysts in hydrogen evolution reaction (HER) from alkaline water is noteworthy, but the obtained HER activity is hugely relies on synergistic catalysis with its accompanying oxophilic component responsible for water dissociation. In addition, the exfoliation of Pt into atomic level and their precise electronic modification could play pivotal role for achieving superb HER performance. Herein, a surfactant-free, facile, wet-chemical protocol is established to develop nanometre-thin, two-dimensional Pt nanosheets (2D-Pt) through ‘surface-surface confined growth’ on 2D- nickel iron layered double hydroxides (LDHs) template. Under an optimized reaction condition, a 2D-Pt/LDH/2D-Pt sandwich structure were realized, where the close proximity of the two 2D-catalytic entities i.e., Pt and oxophilic LDH are recognised to maximize their electronic interaction in the strongly bound nanohybrid. Thus, through judicious installation of layered LDH/2D-Pt interface for the water dissociation and combining with the fast and efficient hydrogen evolution from the on-bound thin and porous 2D-Pt layers, an well-organized interfacial synergy endows the HER performance to reach 6.1 times superior Pt mass utilization than commercial 20% Pt/C at -0.07 V vs RHE, whereas their sandwiched nature of the catalytic entities promote a record-high HER stability over 50 h long electrochemical study. This work highlights the opportunity for merging the exfoliated Pt into atomic level and their strong integration with catalytic in-house LDH surface to challenge remarkable electrochemical HER activity and excellent durability.