Coral-like hierarchical architecture self-assembled by cobalt hexacyanoferrate nanocrystals and N-doped carbon nanoplatelets as efficient electrocatalyst for oxygen evolution reaction

It is challenging to develop novel oxygen evolution reaction (OER) electrocatalysts with high performance and low cost, to replace the noble metal-based catalysts for large-scale electrochemical water splitting. To settle such issue, herein, self-assembled porous coral-like architecture constructed by cobalt hexacyanoferrate (CoHCF) nanocrystals and nitrogen-doped carbon (NC) nanoplatelets network is fabricated for the first time by a facile electroless deposition approach. The porous coral-like CoHCF/NC hybrid exhibits an excellent OER electrocatalytic activity in alkaline medium with an ultra-low onset overpotential of 165 mV (vs. RHE) and a small Tafel slope of 73.97 mV dec(-1), which are much lower than that of bare CoHCF (onset overpotential of 296 mV and Tafel slope of 113.25 mV dec(-1)); it also exhibits a lower overpotential of 357 mV (vs. RHE) at current density of 10 mA cm(-1) and superior durability even after 16 h. The excellent electrocatalytic performance of CoHCF/NC hybrid can be assigned to its unique coral-like architecture self-assembled by CoHCF nanocrystals and NC nanoplatelets network, which significantly increases the electrochemical active surface area and remarkably facilitates the electron and ion transfer. This work offers rational design and facile synthesis strategy for transition metal hexacyanoferrate-based nonprecious electrocatalysts with unique nano-architecture and excellent electrocatalytic efficiency towards OER. (C) 2019 Elsevier Inc. All rights reserved.