Ruthenium-cobalt nanoalloys encapsulated in nitrogen-doped graphene as active electrocatalysts for producing hydrogen in alkaline media

Jianwei Su,Guoliang Xia,Jitang Chen,Qianwang Chen,Peng Jiang,Yang Yang

doi:10.1038/ncomms14969

Abstract

The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Currently, the major challenge confronting hydrogen evolution reaction (HER) is lacking inexpensive alternatives to platinum-based electrocatalysts. Here we report a high-efficient and stable electrocatalyst composed of ruthenium and cobalt bimetallic nanoalloy encapsulated in nitrogen-doped graphene layers. The catalysts display remarkable performance with low overpotentials of only 28 and 218 mV at 10 and 100 mA cm−2, respectively, and excellent stability of 10,000 cycles. Ruthenium is the cheapest platinum-group metal and its amount in the catalyst is only 3.58 wt.%, showing the catalyst high activity at a very competitive price. Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon–hydrogen bond, thereby lowing ΔGH* of HER.

Highlights

The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis
Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon–hydrogen bond, thereby lowing DGH* of hydrogen evolution reaction (HER)
It is of great significance to explore inexpensive alternatives for Pt/C catalyst (Pt) electrocatalysts

Summary

Introduction

The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Electrochemical water splitting, a non-fossil fuel-based technology, is evoking increasing interests and stimulating intense investigations to produce low-costing and high-pure hydrogen[6,7]. As the heart of the scalable hydrogen production, it is of great importance to develop highly efficient electrocatalysts to drive the hydrogen evolution reaction (HER)[8]. It is well known, electrochemical water splitting can be carried out in acidic or alkaline media[2,4]. Tremendous efforts have been devoted to developing HER catalysts with high activity and stability in basic media on the basis of the available alkaline oxygen evolution electrocatalysts, aiming at accelerating commercialization of the basic electrolyzers for H2-production. The pure TM-based catalysts are unable to meet the requirement of replacing Pt-based electrocatalysts

Methods

Results

Conclusion