Enhancement of low-temperature ammonia decomposition over potassium-promoted Ru/MgAl2O4 catalyst for clean hydrogen production

초록

The growing demand for clean hydrogen highlights the importance of efficient hydrogen carriers, with ammonia holding promise because of its high volumetric hydrogen density. Efficient catalysts for the low-temperature ammonia decomposition are essential for realizing its potential as an H2 carrier. Herein, a Ru/MgAl2O4 with a low Ru loading (1.4 wt%) is developed using precalcination under hydrogen to suppress Ru particle sintering and improve Ru dispersion. Potassium was introduced as a promoter to accelerate the rate-determining N2 desorption step by increasing the electron density. The optimal catalyst achieves an NH3 conversion of 90 % at 450 degrees C and a 30,000 mL/(gcat h). CO DRIFT, XPS, and NH3 TPSR are used to determine the optimal K content (7 wt%) and establish a correlation between the Ru electron density and activity. This study facilitates the design and development of cost-effective high-performance ammonia decomposition catalysts with a wide operating temperature window for clean hydrogen production.

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