20November2019

Nano-Micro Letters

Nitrogen-Doped Carbon Encased Bimetallic Selenide for High-Performance Water Electrolysis

Junhui Cao1, Kexin Wang1, Jiayi Chen1, Chaojun Lei1, Bin Yang1, Zhongjian Li1, Lecheng Lei1, Yang Hou1, 2, 3, *, Kostya (Ken) Ostrikov4

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Nano-Micro Lett. (2019) 11: 67

First Online: 08 August 2019 (Article)

DOI:10.1007/s40820-019-0299-4

*Corresponding author. E-mail: yhou@zju.edu.cn (Yang Hou)

 

Abstract

 


Toc

Demand of highly efficient earth-abundant transition metal based electrocatalysts to replace noble-metal materials for boosting oxygen evolution reaction (OER) is rapidly growing. Herein, an electrochemically exfoliated graphite (EG) foil supported bimetallic selenide encased in N-doped carbon (EG/(Co, Ni)Se2-NC) hybrid is developed and synthesized by a vapor-phase hydrothermal strategy and subsequent selenization process. The as-prepared EG/(Co, Ni)Se2-NC hybrid exhibits a core-shell structure where the particle diameter of (Co, Ni)Se2 core is about 70 nm and the thickness of N-doped carbon shell is approximately 5 nm. Benefitting from the synergistic effects between the combination of highly active Co species and improved electron transfer from Ni species, and N-doped carbon, the EG/(Co, Ni)Se2-NC hybrid shows remarkable electrocatalytic activity toward OER with a comparatively low overpotential of 258 mV at an current density of 10 mA cm-2 and a small Tafel slope of 73.3 mV dec-1. The excellent OER catalysis performance of EG/(Co, Ni)Se2-NC hybrid is much better than that of commercial Ir/C (343 mV at 10 mA cm-2 and 98.1 mV dec-1), and even almost the best among all previously reported binary CoNi selenides based OER electrocatalysts. Furthermore, in-situ electrochemical Raman spectroscopy combined with ex-situ X-ray photoelectron spectroscopy analysis indicates that the superb OER catalysis activity can be attributed to the highly active Co-OOH species and modified electron transfer process from Ni element.


 

Keywords

Core-shell-structure; Bimetallic selenide; N-doped carbon; Synergistic effect; Oxygen evolution reaction

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