Vacancy-triggered and dopant-assisted NO electrocatalytic reduction over MoS₂

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nitric oxide electroreduction (NOER) is crucial for ammonia synthesis and pollutant treatment.
• Current NOER catalysts often rely on expensive noble metals or single-atom catalysts.
• Low-cost transition metal dichalcogenides (TMDCs) are under-explored for NOER.

Purpose of the Study:

• Investigate the NOER catalytic performance of 2H-MoS2 monolayers.
• Explore the synergistic effects of sulfur vacancies and transition metal doping on NOER.
• Identify promising TMDC-based catalysts for efficient and selective NOER.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Studied 2H-MoS2 monolayers with sulfur (S) vacancies and transition metal (TM) substitutions (TM-MoS2@VS).
• Analyzed the adsorption, activation, and reaction pathways of NOER and hydrogen evolution reaction (HER).

Main Results:

• A combination of S vacancies and heteroatom doping (1NN pair) significantly enhances NOER activity.
• S vacancies facilitate NO adsorption and bond elongation; heteroatom dopants tune electronic properties.
• Pt-MoS2@VS and Au-MoS2@VS exhibit low onset potentials for NH3 synthesis (-0.06 and -0.38 V, respectively).
• N2O/N2 formation is favored at high NO coverage, while HER is suppressed.
• The strategy of coupled doping and vacancy engineering shows potential for other TMDCs and reactions.

Conclusions:

• Co-doped TM-MoS2@VS catalysts are highly promising for efficient NOER.
• This approach offers a low-cost, high-performance alternative to noble metal catalysts.
• The synergistic strategy can be extended to enhance catalytic properties of other TMDCs.