MoS₂ Nanosheets Functionalized Multichannel Hollow Mo₂N/Carbon Nanofibers as a Robust Bifunctional Catalyst for Water Electrolysis

Abstract

Herein, a heterogeneous system composed of few-layered MoS2 nanosheets functionalized multichannel hollow carbon nanofibers containing Mo2N (Mo2N–MoS2 MCNFs) was successfully developed for the hydrogen/oxygen evolution reactions (HER/OER). The obtained Mo2N–MoS2 MCNFs manifests superior performance with improved durableness for electrocatalysis. Independently, at 10 mA cm–2, the optimal Mo2N–MoS2(1:1) MCNFs achieves overpotentials (η10) of 131 mV for HER and 270 mV for OER. The intimate interaction between the few-layered MoS2 nanosheets array and 1D multichannel hollow carbon nanofibers Mo2N (Mo2N/Carbon MCNFs) advances better exposure of dynamic heterointerfaces, improves the conductivity of electron transfer, and enriches active sites with efficient mass transport. When employed to drive the water electrolysis, Mo2N–MoS2(1:1) MCNFs also demonstrates a modest overall potential of merely 1.63 V to hit 10 mA cm–2. This study will provide a well-designed structure and development for functional materials in electrochemical energy storage and conversion devices.

Atomically Dispersed Mo Sites Anchored on Multichannel Carbon Nanofibers toward Superior Electrocatalytic Hydrogen Evolution

“…On the basis of the aforementioned experimental findings and theoretical calculations, the high-efficiency HER performance of Mo@NMCNFs can be attributed to the following synergistic aspects: (1) The coordination of Mo sites with nonmetallic atoms of C, N, and O on an atomic scale could dramatically modify the electronic reconfiguration of Mo single atoms, and the abundant atomically dispersed Mo active sites with a coordination microenvironment endow the formed Mo@NMCNFs with favorable hydrogen adsorption energy and thus improved intrinsic activity . (2) The “lotus root”-structured CNFs with cavities and open internal multichannels could render the reactive sites more accessible and promote mass transport, electrolyte permeation, and gas release, enormously accelerating the reaction kinetics . (3) The firm immobilization of Mo single atoms within the porous multichannel porous carbon substrate could efficaciously inhibit the undesirable reconstruction and agglomeration of the metal active sites to form bigger clusters or nanoparticles during the long-term electrocatalytic course, rendering outstanding mechanical stability.…”

“…46 (2) The "lotus root"structured CNFs with cavities and open internal multichannels could render the reactive sites more accessible and promote mass transport, electrolyte permeation, and gas release, enormously accelerating the reaction kinetics. 47 (3) The firm immobilization of Mo single atoms within the porous multichannel porous carbon substrate could efficaciously inhibit the undesirable reconstruction and agglomeration of the metal active sites to form bigger clusters or nanoparticles during the long-term electrocatalytic course, rendering outstanding mechanical stability. (4) The N doping into the carbon matrix is propitious for enhancing the electric conductivity of the carbon current collector, increasing the surface hydrophilic properties, and altering the chemisorption behavior of the H atom.…”

Versatile Graphitized Carbon Nanofibers in Energy Applications

“…The stacked graphene sheets of diverse shapes can generate more edge sites on the outer wall of CNFs, and this is the primary factor that making a distinction of CNFs from CNTs. ,,− CNFs are longer than the CNTs, have a larger diameter, and grow at comparatively lower temperatures but do not have a hollow cavity. , The 1D structures of CNFs reduce the diffusion lengths of ions in radial orientation and provide abundant active sites and voids to load active material. ,, CNFs have somewhat lower surface areas as well as electrical conductivities compared to CNTs but still have lower manufacturing costs and compatibility with industrial mass production and are easy to disperse, making them potential candidates for energy storage applications and power management apart from other uses in sensors, tissue engineering, and more.…”

“…The high durability of ZIF-8/ZIF-67-derived, Co-N x -embedded CNFs was ascribed to enhance the structural stability and graphitization degree . Integrating the hollow CNFs with transition metal dichalcogenides such as MoS 2 and WS 2 is also an interesting approach toward fabricating effectual electrocatalysts. , Xie et al prepared Mo 2 N/multichannel hollow CNFs (Mo 2 N/carbon MCNFs) functionalized by flake-shaped few-layered MoS 2 nanosheets (Mo 2 N-MoS 2 MCNFs). The graphitic order of the final material (with 1:1 ratio) was higher than Mo 2 N/carbon MCNFs owing to the successful amalgamation of MoS 2 and Mo 2 N/carbon MCNFs that could lead to a unique heterostructure.…”

Synthesis of MoS2-based nanostructures and their applications in rechargeable ion batteries, catalysts and gas sensors: a review

“… 64 MoS 2 compounded with Mo 2 N-containing multichannel hollow CNFs (Mo 2 N–MoS 2 MCNFs) also possesses excellent HER and OER catalytic properties. 65 Subsequently, the preparation of these materials will be described.…”