A new high efficiency catalyst of Co–Ni/CeO2 for hydrogen production by ammonia oxidative decomposition at low temperature

Abstract

Hydrogen production through ammonia decomposition at high temperatures is a promising approach, but lacks a simple and cost-effective process for efficient and rapid initiation of ammonia decomposition without external energy. To address this, the preparation of nanomaterials is crucial to achieve excellent ammonia oxidative decomposition performance. In this study, CeO2 with an ordered mesoporous structure was synthesized and supported with Co and Ni bimetals using a co-deposition method. Through various experimental characterization methods (XRD, BET, TEM, H2-TPR and XPS), a structure-activity relationship was established and a catalytic reaction mechanism was proposed. The catalyst with the best activity performance was found to be 5 wt % Co-5wt % Ni/CeO2 (CNC-55). With an NH3/O2 ratio of 4:1, the reaction temperature increased rapidly from 130 °C to 570 °C, the NH3 and O2 conversion rate can reach 95% and 100% respectively, and the H2 production rate can reaches 62%. The catalyst also exhibited good stability and reusability. Notably, the process only required ammonia and oxygen at low temperatures to produce hydrogen, nitrogen and water vapor, without the need for external energy or additional procedures.