Ambient pressure ammonia decomposition using Ga–Co supported catalytically active liquid metal solutions

Abstract

Ga–Co supported catalytically active metal solutions (SCALMS) on silicon carbide (SiC) were successfully tested for ambient pressure ammonia decomposition in the temperature range between 480 and 580 °C. Comparison studies of a Ga₅₉Co SCALMS system with their monometallic equivalents Co/SiC and Ga/SiC revealed a massively enhanced ammonia decomposition activity of the supported alloy catalyst. The Ga₅₉Co/SiC outperformed a monometallic benchmark Co/SiC catalyst in terms of the Co specific H₂ productivity by up to one order of magnitude. Monometallic Ga/SiC, in contrast, showed no activity for ammonia decomposition up to 580 °C. We report productivities of 487 g_H2 g_Co⁻¹ h⁻¹ at 5% conversion and 550 °C at a weight hourly space velocity (WHSV) of 29 000 mL_N g_cat⁻¹ h⁻¹ for our SCALMS system. Apparent activation energies (E_A,app) determined from temperature variation experiments give no indication for diffusion limitations under the applied reaction conditions. Therefore, we present a new catalyst material concept for ammonia decomposition with high potential for practical and technical application.