Nickel phyllosilicate derived RuNi catalyst for ammonia decomposition to hydrogen

This study reports a stable catalyst for NH 3 decomposition to hydrogen. The precursor of SiO 2 @NP was prepared by hydrothermal method, and the hydrothermal treatment of spherical SiO 2 results in etching of SiO 2 and the formation of nickel phyllosilicate, which greatly increase specific surface area of the catalyst. Ru is loaded onto the SiO 2 @NP by incipient wetness impregnation, forming the catalyst 1Ru/SiO 2 @NP. At a gas hourly space velocity (GHSV) of 30,000 mL NH3 (g × h) −1 and 650 °C, the conversion of ammonia over 1Ru/SiO 2 @NP reaches 98%. Furthermore, the catalyst maintains excellent stability during a period of 210 h at 600 °C. To investigate the origination of activity and stability, various characterizations have been used. In its reduced form, Ni and Ru stay metallic, and Ru–Ni interactions are realized. Both high specific surface area and Ru–Ni interactions allow the generation of small metallic particles that are resistant to sintering during reaction process, thus improving the activity and stability of the catalyst. This study provides new insights and references for the preparation of efficient and stable catalysts for NH 3 decomposition.