Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution.

Guangsheng Liu,Wenting Chen,Xuefeng Lv,Tingjun Lin,Shipeng Tan,Kunyapat Thummavichai,Yanqiu Zhu,Yu Chen,Minli Zeng,Nannan Wang

doi:10.3390/nano11030662

Guangsheng Liu, Wenting Chen + Show 8 more

Open Access

https://doi.org/10.3390/nano11030662

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Journal: Nanomaterials	Publication Date: Mar 8, 2021
Citations: 20	License type: CC BY 4.0

Affiliation: Guangxi University

Abstract

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

Highlights

Hydrogen energy is expected to be an ideal energy source in the future due to its high energy density and zero pollution [1,2]
The MoS2 /reduced graphene oxide (rGO)/NiS nanocomposite with rich defects and heterogeneous interfaces was synthesized by two-step hydrothermal method, which is shown in Figure 1. (The detailed synthesized steps were in supporting information)
The αNi(OH)2 adsorbed on the GO was sandwiched between the GO and the MoS2 nanosheets and was vulcanized into NiS, while the GO was in situ reduced to reduced graphene oxide during the hydrothermal process

Summary

Introduction

Hydrogen energy is expected to be an ideal energy source in the future due to its high energy density and zero pollution [1,2]. Few active sites, intrinsic low conductivity and insufficient stability hinder the HER activity of MoS2 [8] To solve these problems, various effective methods such as defect and interfaces engineering, structural design and elements doping technique have been introduced for improving electrocatalytic activity of. The reported CoS2 @MoS2 /rGO [19], MoS2 /rGO [25] and Mn/MoS2 /rGO [26] catalysts have good catalytic stability and electrocatalytic activity, which owes to the synergetic effect of rGO intrinsic high charge conduction characteristics [23]. Defect-rich multiphase MoS2 /rGO/NiS nanocomposite catalyst was successfully synthesized using αNi(OH) nanowires with excellent catalytic performance and stability over a wide range of pH.

Results and Discussion

After modest overpotential

Conclusions