Engineering the Electronic Structure of MoS₂ Nanorods by N and Mn Dopants for Ultra-Efficient Hydrogen Production

Abstract

Developing economical and efficient electrocatalysts with nonprecious metals for the hydrogen evolution reaction (HER), especially in water-alkaline electrolyzers, is pivotal for large-scale hydrogen production. Recently, both density functional theory (DFT) calculations and experimental studies have demonstrated that earth-abundant MoS 2 is a promising HER electrocatalyst in acidic solution. However, the HER kinetics of MoS 2 in alkaline solution still suffer from a high overpotential (90−220 mV at a current density of 10 mA cm −2 ). Herein, we report a combined experimental and first-principle approach toward achieving an economical and ultraefficient MoS 2 -based electrocatalyst for the HER by fine-tuning the electronic structure of MoS 2 nanorods with N and Mn dopants. The developed N,Mn codoped MoS 2 catalyst exhibits an outstanding HER performance with overpotentials of 66 and 70 mV at 10 mA cm −2 in alkaline and phosphate-buffered saline media, respectively, and corresponding Tafel slopes of 50 and 65 mV dec −1 . Moreover, the catalyst also exhibits long-term stability in HER tests. DFT calculations suggest that (1) the electrocatalytic performance can be attributed to the enhanced conductivity and optimized electronic structures for facilitating H* adsorption and desorption after N and Mn codoping and (2) N and Mn dopants can greatly activate the catalytic HER activity of the Sedge for MoS 2 . The discovery of a simple approach toward the synthesis of highly active and low-cost MoS 2 -based electrocatalysts in both alkaline and neutral electrolytes allows the premise of scalable production of hydrogen fuels.

Oxygen‐Functionalized Ultrathin Ti3C2Tx MXene for Enhanced Electrocatalytic Hydrogen Evolution

“…The electrochemical double‐layer capacitance (C dl ) of E‐Ti 3 C 2 O x is measured to be 12.9 mF cm −2 , which is much higher than that of E‐Ti 3 C 2 (OH) x and E‐Ti 3 C 2 T x ‐450 (Figure S7). These results reveal that heat treatment can increase the number of exposed active sites for Ti 3 C 2 ‐based catalysts . Unexpectedly, the specific HER activity of E‐Ti 3 C 2 O x is lower than that of E‐Ti 3 C 2 (OH) x (Figure S8) upon normalizing with respect to C dl .…”

Doping‐Assisted Phase Changing Effect on MoS2 Towards Hydrogen Evolution Reaction in Acidic and Alkaline pH

“…The HER performance is comparable with recently reported MoS 2 ‐based electrocatalysts . It may be due to the improved in‐plane electrical conductivity and carrier concentration of MoS 2 after nitrogen doping as observed in earlier cases for the nitrogen‐manganese co‐doped MoS 2 and nickel@N‐doped carbon@MoS 2 systems . Therefore, the HER activity enhancement can be related to the N dopants in the MoS 2 crystal structure.…”

“…The calculated Tafel slope value of the above three reactions were 118, 39, and 29 mV dec −1 . For all the prepared materials, the Tafel slope values varied within 70–48 mV dec −1 range which represented the Volmer‐Heyrovsky mechanism for HER process . As presented in Figure b, Tafel slope decreased from 68.8 to 48.2 mV dec −1 after successive N doping.…”

“…These observations notified the presence of N in NMSd and modified the phase . [38] Generally, the peak at~396 eV reflected the formation of N-Metal-S, which indicated the replacement of S ion by N ion. [39] The atomic percentage of all the prepared compositions were calculated and summarized from survey spectra analysis in supporting information (depicted in Table S1).…”

Stimulated Electrocatalytic Hydrogen Evolution Activity of MOF‐Derived MoS2 Basal Domains via Charge Injection through Surface Functionalization and Heteroatom Doping

“…[15][16][17][18][19] By breaking the periodicity in MoS 2 crystal and reconfiguring it with alien atoms, it is possible to create localized electronic density on host atoms, hence altering the energy barriers for the reaction. [15][16][17][18][19] By breaking the periodicity in MoS 2 crystal and reconfiguring it with alien atoms, it is possible to create localized electronic density on host atoms, hence altering the energy barriers for the reaction.…”