Harmonious Heterointerfaces Formed on 2D-Pt Nanodendrites by Facet-Respective Stepwise Metal Deposition for Enhanced Hydrogen Evolution Reaction.

The performance of nanocrystal (NC) catalysts could be maximized by introducing rationally designed heterointerfaces formed by the facet- and spatio-specific modification with other materials of desired size and thickness. However, such heterointerfaces are limited in scope and synthetically challenging. Herein, we applied a wet chemistry method to tunably deposit Pd and Ni on the available surfaces of porous 2D-Pt nanodendrites (NDs). Using 2D silica nanoreactors to house the 2D-PtND, an 0.5-nm-thick epitaxial Pd or Ni layer (e-Pd or e-Ni) was exclusively formed on the flat {110} surface of 2D-Pt, while a non-epitaxial Pd or Ni layer (n-Pd or n-Ni) was typically deposited at the {111/100} edge in absence of nanoreactor. Notably, these differently located Pd/Pt and Ni/Pt heterointerfaces experienced distinct electronic effect to influence unequally in electrocatalytic synergy for hydrogen evolution reaction (HER). For instance, an enhanced H2 generation on the Pt{110} facet with 2D-2D interfaced e-Pd deposition and faster water dissociation on the edge-located n-Ni overpowered their facet-located counterparts in respective HER catalysis. Therefore, a feasible assembling of the valuable heterointerfaces in the optimal 2D n-Ni/e-Pd/Pt catalyst overcame the sluggish alkaline HER kinetics, with a catalytic activity 7.9 times higher than that of commercial Pt/C.