ZrN₆ -Doped Graphene for Ammonia Synthesis: A Density Functional Theory Study

Area of Science:

• Catalysis
• Materials Science
• Computational Chemistry

Background:

• Ammonia is crucial for the chemical industry.
• Efficient catalysts for nitrogen (N2) to ammonia (NH3) conversion are highly sought after.
• Transition metal-anchored graphene is a potential catalyst platform.

Purpose of the Study:

• To investigate the electrocatalysis of transition metal atom anchored graphene for nitrogen fixation.
• To identify promising catalyst configurations for ammonia synthesis.
• To understand the mechanism of catalysis at the atomic level.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Systematic investigation of six-coordinated transition metal atoms anchored on graphene.
• Free energy analysis and electron transfer analysis were performed.

Main Results:

• The ZrN6 configuration demonstrated good activity for ammonia synthesis at an overpotential of 0.51 V.
• The ZrN6 site facilitates charge transfer between graphene and reactants.
• N6 coordination enhances electron accumulation on intermediates, weakening the N-N bond and reducing the protonation barrier.

Conclusions:

• ZrN6 anchored on graphene is a promising catalyst for electrocatalytic ammonia synthesis.
• The coordination environment plays a critical role in tuning catalytic activity.
• This study provides fundamental insights into metal-graphene interactions for nitrogen fixation.