Ammonia (NH3) decomposition is a promising route for hydrogen production. This work compares external wall-heated reactor (EWHR) and internal Joule-heated reactor (IJHR) to clarify the influence of heating mode, heater architecture, and catalyst deployment on transfer and reaction. IJHR delivers higher NH3 conversion than EWHR, reaching 21.0% at 180 mL/min, indicating improved robustness under elevated heat demand. Under internal Joule heating mode, foam architecture provides more uniform temperature distribution and higher energy utilization, achieving 3.2% higher conversion. Catalyst deployment on conductive foam is then evaluated by comparing packed and coated implements, followed by tuning coating loading. Coated-foam architecture boosts heat transfer and NH3 conversion at intermediate temperatures, whereas diffusion within the thicker coating layer limits benefits at higher temperatures. Optimized coating achieves conversion comparable to packed foam with 46.7% less catalyst, improving catalyst utilization. These results provide guidance for scaling reactors by balancing heat supply, temperature uniformity, and catalyst utilization.
Sui et al. (2026) studied this question.