Tandem Electrocatalytic Nitrate Reduction to Ammonia on MBenes

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic nitrate reduction to ammonia (NO3 RR) is crucial for sustainable nitrogen management and ammonia synthesis.
• Developing efficient and selective catalysts for NO3 RR remains a significant challenge.

Purpose of the Study:

• To explore the feasibility of MBenes as a novel class of tandem catalysts for electrocatalytic NO3 RR.
• To investigate the catalytic performance and mechanism of FeB2 as a model MBene catalyst for NO3 RR.

Main Methods:

• Electrochemical measurements, including polarization curves and Faradaic efficiency determination.
• Synthesis and characterization of FeB2 as a MBene catalyst.
• Mechanistic studies to elucidate the role of different sites in the tandem catalysis.

Main Results:

• FeB2 exhibited excellent NO3 RR activity, achieving a maximum NH3 Faradaic efficiency of 96.8% and a yield of 25.5 mg h-1 cm-2 at -0.6 V vs. RHE.
• Mechanistic studies revealed a tandem catalysis pathway where B sites activate nitrate and Fe sites facilitate hydrogen evolution.

Conclusions:

• MBenes represent a promising new class of catalysts for efficient electrocatalytic NO3 RR.
• The tandem catalysis mechanism in FeB2, involving synergistic B and Fe sites, is key to its high performance.