Adsorption Behavior of Ammonia on Strontium Bromide Surface: First-Principles Study

Area of Science:

• Materials Science
• Chemical Engineering
• Energy Storage

Background:

• Thermochemical heat storage offers effective long-term energy solutions, particularly for industrial waste heat and solar energy.
• Ammonium halides are recognized for their thermodynamic properties in thermochemical heat storage, though research remains at the laboratory scale.

Purpose of the Study:

• To investigate the atomic-scale adsorption behavior of ammonia on strontium bromide surfaces.
• To explore the impact of metal doping on the thermochemical performance of the SrBr2/NH3 working pair.

Main Methods:

• Density functional theory (DFT) calculations were employed to study the SrBr2/NH3 system.
• The optimal adsorption sites for ammonia on strontium bromide were identified.
• The effects of magnesium (Mg) and calcium (Ca) doping on the reaction energy barrier were analyzed.

Main Results:

• The intrinsic energy barrier for the SrBr2/NH3 reaction was determined.
• Mg doping slightly reduced the energy barrier to 4.145 kcal/mol.
• Ca doping significantly decreased the energy barrier to 0.727 kcal/mol, indicating enhanced thermochemical performance.

Conclusions:

• Calcium doping demonstrates a substantial optimization effect on the thermochemical heat storage process for the SrBr2/NH3 system.
• The findings provide insights into the adsorption mechanisms and facilitate the design of advanced composite adsorbents for efficient heat storage.