High electrocatalytic performance of bimetallic sulfides dodecahedral nanocages (CoxM1-x)9S8/M/N-C (M=Ni, Cu) for triiodide reduction reaction and oxygen evolution reaction

Electrocatalysis is the key process for many important energy conversion reaction, such as water splitting and CO2 reduction. The development of high efficiency electrocatalysts has attracted more attention in the field of electrochemistry and photovoltaic cell. Here, a simple cation exchange method is used to prepare the bimetallic sulfides ((CoxM1- x)(9)S-8/M/N-C, M = Ni or Cu) dodecahedral nanocages (DNCs), in which (CoxM1- x)(9)S-8 nanoparticles are coated with N-doped carbon shell. Bimetallic sulfides exhibit enhanced electrocatalytic property for triiodide reduction reaction and oxygen evolution reaction (OER) owing to favorable compositional features and well-designed architectures. The catalytic activities extremely depend on the atom ratio of Co:M and the component. Remarkably, (Co0.75Ni0.25)(9)S-8/N-C DNCs deliver the best electrocatalytic activity for the triiodide reduction reaction using as the low-cost Pt-free counter electrode (CE) in dye-sensitized solar cells (DSSCs). Furthermore, (Co0.64Ni0.36)(9)S-8/Ni/N-C-1 DNCs as an OER catalyst exhibit excellent electrocatalytic property in the light of the low overpotential (326 mV) at the current density of 10 mA cm(-2). This notion and expedient method of construction can be broadened to synthesize other bimetallic sulfides with preferable electrocatalytic performance. (C) 2019 Elsevier Ltd. All rights reserved.