Plasma-Driven Dual-Membrane System for Intensified Hydrogen Production with Integrated Ammonia Recovery.

Area of Science:

• Materials Science
• Chemical Engineering
• Catalysis

Background:

• Ammonia (NH3) is a key carbon-free hydrogen (H2) carrier.
• Conventional thermocatalysis for NH3 decomposition requires high temperatures, limiting efficiency.
• In situ product removal is challenging for mild-condition NH3 decomposition.

Purpose of the Study:

• To develop a plasma-enhanced dual-membrane system for efficient ammonia decomposition.
• To achieve high H2 production yields under mild conditions.
• To enable energy-efficient NH3 recovery and purification.

Main Methods:

• Utilized a plasma-enhanced dual-membrane ammonia decomposition system (PEDMADS).
• Coupled dielectric barrier discharge (DBD) with an atomic layer deposition (ALD)-synthesized Ru/SiO2 catalyst and an ultrathin Pd membrane.
• Employed a cascade of Silicalite-1 (S-1) membranes for NH3 recovery.
• Performed molecular dynamics simulations to understand separation mechanisms.

Main Results:

• Achieved a high H2 space-time yield of 1567 mmol g-1 h-1 at 400 °C.
• Demonstrated unprecedented NH3/H2 (686) and NH3/N2 (7076) separation factors using S-1 membranes.
• Reduced effluent NH3 concentration from 24.1% to below 4% with 87% removal efficiency.
• Simulations revealed preferential adsorption-driven molecular sieving for selectivity.

Conclusions:

• The PEDMADS offers a promising approach for sustainable hydrogen production from ammonia.
• The integrated membrane system enables efficient NH3 decomposition and recovery under mild conditions.
• Techno-economic analysis shows a low cost ($0.92/kg H2) and reduced carbon footprint, supporting a hydrogen economy.