Free-standing bimetallic CoNiTe_2 nanosheets as efficient catalysts with high stability at large current density for oxygen evolution reaction

摘要

The oxygen evolution reaction (OER) step for water splitting requires highly efficient, low-cost and stable catalysts. As efficient catalytic materials for OER, bimetallic telluride (CoNiTe2/NF) nanosheets are prepared by the combination of hydrothermal and calcination method in this work. The physicochemical characterizations confirm that the surface of CoNiTe2/NF is covered by bimetallic telluride compounds (CoNiTe2) with 3D morphology composed of thin and defective nanosheets that are well-distributed on nickel foam (NF). Notably, it shows very low overpotential at 10 (181 mV), 500 (230 mV) and 1000 (270 mV) mA cm(-2) and low Tafel slope (44 mV dec(-1)). Besides, it also exhibits excellent durability lasting 24 h at 100, 500 and 1000 mA cm(-2), respectively, without distinct deactivation. This outstanding performance could be due to the bimetallic telluride and the strong covalency around the CoNi center caused by Te that plays a crucial role for enhancing the activity of catalyst. The unique morphology could provide large electrochemical active area and exposure higher amounts of active sites. Meanwhile, the self-supported structure, without binders, could also enhance the performance for OER. This work thus provides a promising strategy to synthesize multi-metal telluride materials as highly efficient and stable catalyst for OER at large current density. (C) 2020 Elsevier Ltd. All rights reserved.