Hydrogen evolution reaction from bare and surface-functionalized few-layered MoS2 nanosheets in acidic and alkaline electrolytes

B Lai; Subhash C Singh; J K Bindra; C S Saraj; A Shukla; T P Yadav; W Wu; S A McGill; N S Dalal; Amit Srivastava; Chunlei Guo

doi:10.1016/j.mtchem.2019.100207

Hydrogen evolution reaction from bare and surface-functionalized few-layered MoS₂ nanosheets in acidic and alkaline electrolytes

Mater Today Chem. 2019 Dec:14:100207. doi: 10.1016/j.mtchem.2019.100207.

Authors

B Lai^{1

2}, Subhash C Singh^{1

2}, J K Bindra³, C S Saraj², A Shukla², T P Yadav⁴, W Wu², S A McGill⁵, N S Dalal³, Amit Srivastava^{3

6}, Chunlei Guo^{1

2}

Affiliations

¹ The Institute of Optics, University of Rochester, Rochester, NY, 14627, USA.
² Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033, China.
³ Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
⁴ Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, 222005, India.
⁵ National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 30201, USA.
⁶ Department of Physics, TDPG College, VBS Purvanchal University, Jaunpur, 222001, India.

Abstract

Hydrogen is considered as an ideal and sustainable energy carrier because of its high energy density and carbon-free combustion. Electrochemical water splitting is the only solution for uninterrupted, scalable, and sustainable production of hydrogen without carbon emission. However, a large-scale hydrogen production through electrochemical water splitting depends on the availability of earth-abundant electrocatalysts and a suitable electrolyte medium. In this article, we demonstrate that hydrogen evolution reaction (HER) performance of electrocatalytic materials can be controlled by their surface functionalization and selection of a suitable electrolyte solution. Here, we report syntheses of few-layered MoS₂ nanosheets, NiO nanoparticles (NPs), and multiwalled carbon nanotubes (MWCNTs) using scalable production methods from earth-abundant materials. Magnetic measurements of as-produced electrocatalyst materials demonstrate that MoS₂ nanoflakes are diamagnetic, whereas surface-functionalized MoS₂ and its composite with carbon nanotubes have strong ferromagnetism. The HER performance of the few-layered pristine MoS₂ nanoflakes, MoS₂/NiO NPs, and MoS₂/NiO NPs/MWCNT nanocomposite electrocatalysts are studied in acidic and alkaline media. For bare MoS₂, the values of overpotential (η₁₀) in alkaline and acidic media are 0.45 and 0.54 V, respectively. Similarly, the values of current density at 0.5 V overpotential are 27 and 6.2 mA/cm² in alkaline and acidic media, respectively. The surface functionalization acts adversely in the both alkaline and acidic media. MoS₂ nanosheets functionalized with NiO NPs also demonstrated excellent performance for oxygen evolution reaction with anodic current of ~60 mA/cm² and Tafel slope of 78 mVdec^-1 in alkaline medium.

Keywords: Acidic and alkaline electrolytes; Ferromagnetic electrocatalysts; Hydrogen evolution reaction; Molybdenum disulfide; Multiwalled carbon nanotubes; Oxygen evolution reaction.