Phase Modulation of (1T‐2H)‐MoSe2/TiC‐C Shell/Core Arrays via Nitrogen Doping for Highly Efficient Hydrogen Evolution Reaction

Abstract

Tailoring molybdenum selenide electrocatalysts with tunable phase and morphology is of great importance for advancement of hydrogen evolution reaction (HER). In this work, phase- and morphology-modulated N-doped MoSe /TiC-C shell/core arrays through a facile hydrothermal and postannealing treatment strategy are reported. Highly conductive TiC-C nanorod arrays serve as the backbone for MoSe nanosheets to form high-quality MoSe /TiC-C shell/core arrays. Impressively, continuous phase modulation of MoSe is realized on the MoSe /TiC-C arrays. Except for the pure 1T-MoSe and 2H-MoSe , mixed (1T-2H)-MoSe nanosheets are achieved in the N-MoSe by N doping and demonstrated by spherical aberration electron microscope. Plausible mechanism of phase transformation and different doping sites of N atom are proposed via theoretical calculation. The much smaller energy barrier, longer HSe bond length, and diminished bandgap endow N-MoSe /TiC-C arrays with substantially superior HER performance compared to 1T and 2H phase counterparts. Impressively, the designed N-MoSe /TiC-C arrays exhibit a low overpotential of 137 mV at a large current density of 100 mA cm , and a small Tafel slope of 32 mV dec . Our results pave the way to unravel the enhancement mechanism of HER on 2D transition metal dichalcogenides by N doping.

Sulfiphilic Few‐Layered MoSe2 Nanoflakes Decorated rGO as a Highly Efficient Sulfur Host for Lithium‐Sulfur Batteries

“…The diameter of the MoSe 2 nanoflakes is only several tens of nanometers without notable aggregation or stacking, further demonstrated by the low-magnification TEM images in Figure 1C,D. [41] Energydispersive X-ray spectrum (EDX; Figure S1, Supporting Information) analysis verifies the formation of MoSe 2 @rGO hybrid with C, O, Mo, and Se as the main elemental components, which is in agreement with the X-ray photoelectron spectroscopy (XPS) results below. Apparently, the characteristic layer structure of MoSe 2 is clearly observable and the nanoflakes are composed of sever layers of MoSe 2 with the interlayer spacing of 0.68 nm.…”

Transition Metal Selenides for Electrocatalytic Hydrogen Evolution Reaction

“…got a mixed (1T‐2H)‐MoSe 2 nanosheets. Due to the smaller energy barrier, longer H−Se bond length, and diminished bandgap, the obtained nanosheets displayed a low overpotential of 137 mV at a large current density of 100 mA cm −2 and a small Tafel slope of 32 mV dec −1 for HER in acidic media . Qu et al.…”

Bacterium, Fungus, and Virus Microorganisms for Energy Storage and Conversion

“…Carbon‐based materials have stimulated great interest as catalysts in hydrogen evolution reaction (HER), ORR, etc. However, pure carbon materials with little defects and active sites are electrochemically inert and exhibit inferior catalytic abilities.…”