Modulating Nitrogen Adsorption Mode and Microenvironment of Active Sites for Boosting Electrochemical Nitrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical reduction of nitrogen (NRR) is a sustainable alternative to the Haber-Bosch process for ammonia synthesis.
• Challenges in NRR include activating N2 and suppressing the competing hydrogen evolution reaction (HER).

Purpose of the Study:

• To develop an efficient electrocatalyst for NRR using ultrafine ruthenium (Ru) nanoclusters confined by a hydrophobic molecular layer on Ti3C2Tx.
• To investigate the catalyst's performance and understand the underlying mechanisms for enhanced NRR and suppressed HER.

Main Methods:

• Fabrication of Ru nanoclusters on Ti3C2Tx with a hydrophobic molecular layer.
• Electrochemical measurements including NRR and HER performance evaluation.
• Experimental and theoretical calculations to elucidate the catalytic mechanism.

Main Results:

• Ultrafine Ru nanoclusters on Ti3C2Tx form paired active sites for low-energy N2 chemisorption.
• The hydrophobic layer enhances N2 accumulation and suppresses water diffusion, increasing N2 concentration and reducing HER.
• Achieved an ammonia yield rate of 33.5 µg h⁻¹ mg⁻¹cat and Faradaic efficiency of 65.3% at -0.25 V vs RHE.

Conclusions:

• The developed electrocatalyst demonstrates superior performance for NRR compared to previous Ti3C2Tx-derived catalysts.
• This work offers a valuable strategy for designing advanced electrocatalysts by controlling active sites and local microenvironments.
• The findings pave the way for more efficient and sustainable ammonia synthesis.