Abstract
In this study, a top-down and site-selective anion etching method is devised to stepwisely carve out the NiCo (OH)(2)/NiS2 concave hetero-cages (CHCs) from NiCo Prussian blue analogue (PBA) cube. DFT calculation investigates that the synthetic mechanism is based on anisotropic reactivity of each etchant acted in different facets of NiCo PBA cube and can be generalized to various heterogeneous combinations by tuning their dissolution and reconstitution kinetics (i.e. NiCoB/NiS2, NiCoP/NiS2). Such strategy without adding extra metal source generates strongly coupled heterointerface with hollow, concave, and ultrathin (similar to 16.2 nm) features, which could harvest abundant active sites, tune the electronic structure, and induce strong lattice strain of Ni. Specifically, the NiCo (OH)(2)/NiS2 CHCs manifest superior activity and stability toward oxygen evolution reaction (OER), with an overpotential of 258.0 mV required for 10.0 mA cm(-2), a Tafel slope of 38.3 mV dec(-1), and favorable long-term durability in 1.0 M KOH.
NSTL
Elsevier