Facile synthesis of Ni 3 S 2 /rGO nanosheets composite on nickel foam as efficient electrocatalyst for hydrogen evolutio
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ie Zhou,a) Zhaohui Hou, and Gangyong Li School of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang, People’s Republic of China
Yafei Kuangb) College of Chemistry and Chemical Engineering, Hunan University, Changsha, People’s Republic of China (Received 29 April 2017; accepted 16 June 2017)
Three-dimensional Ni3S2-reduced graphene oxide (rGO) nanosheets composite is directly grown on nickel foam (Ni3S2-rGO@NF) by a one-step hydrothermal process involving in situ sulfurization of NF and reduction of GO. The introduction of GO is found not only to control the aggregation and the growth of Ni3S2 nanosheets, but also to increase the number of active sites and improve conductivity of composite. The heterogeneous Ni3S2-rGO@NF electrode as electrocatalysts for hydrogen evolution reaction (HER) exhibits significantly enhanced catalytic activity in alkaline media. The onset potential of Ni3S2-rGO@NF can be as low as ;0 mV, which is comparable to platinum, and only a small overpotential of ;44 mV is needed to reach a benchmark current density of 10 mA/cm2. Moreover, it demonstrates a good stability. All evidences suggest that the in situ surfurization can be considered as an effective way to prepare metal sulfides as electrocatalysts for hydrogen generation.
I. INTRODUCTION
Hydrogen production from electrocatalytic splitting of water to minimize global carbon emissions and to maintain sustainability is compelling.1 To achieve this goal, highly active catalysts for the hydrogen evolution reaction (HER) are indispensable.2 Noble metals, such as platinum (Pt), have been considered as one of state-ofthe-art catalysts for HER in acidic medium because their free energy of hydrogen adsorption is approximately zero.3–5 Unfortunately, the high cost and scarcity seriously hinder its widespread application. It is imperative to design efficient kinds of HER catalyst that are made from earth-abundant elements. Indeed, tremendous efforts have been devoted in developing precious metal-free catalysts with high activity for HER over the past years.6–15 Among various materials, transition metal dichalcogenides (TMDs) have attracted increasing attention owing to their high catalytic activity.7–15 Experimental and theoretical studies showed that the HER performances Contributing Editor: Xiaobo Chen Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] DOI: 10.1557/jmr.2017.270
of TMDs were directly related to their composition,16–20 exposed active edge sites,4,7,9,21–23 and conductive substrates.7,24–30 Recently, various nanostructured Ni-based TMDs demonstrated impressive performances in HER.2,31,32 Particularly, Ni3S2 nanomaterial has been considered as one of the promising candidates for HER due to its low cost, high abundance, and easy preparation processing.33–38 Many studies showed that the electrocatalytic activities of three-dimensional (3D) Ni3S2 supported on Ni foam were higher than those of the molybdenum dichalcogenides in basic media because of their i
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