负载型双金属催化剂的制备及其等离子体催化氨分解制氢性能

Preparation and Performance of Supported Bimetallic Catalysts for Hydrogen Production from Ammonia Decomposition by Plasma Catalysis

利用等体积浸渍法制备了Fe-Co、Fe-Ni、Mo-Co、Mo-Ni双金属催化剂(总金属含量均为10%(w,质量分数),双金属摩尔比均为1:1),考察了其在等离子体条件下氨分解活性,结果表明Fe-Ni双金属催化剂表现出较好的协同作用。在此基础上,进一步考察了Fe/Ni摩尔比对其活性的影响。结果表明:当Fe/Ni摩尔比为6/4时,氨分解活性最好,而且该双金属催化剂稳定性良好。采用N_2物理吸附、X射线衍射(XRD)、H_2-程序升温还原(H_2-TPR)和高分辨透射电子显微镜(HRTEM)对催化剂的物化性质、还原性能、微观形貌等进行了研究。结果表明:活性较好的Fe-Ni双金属催化剂中,Fe与Ni形成尖晶石结构NiFe_2O_4,该结构有利于Fe和Ni的还原,即活性组分易恢复金属态,这可能是其活性较高的原因。

Bimetallic Fe-Co, Fe-Ni, Mo-Co, and Mo-Ni catalysts, with total metal contents of 10 wt% and bimetallic molar ratios of 1：1, were prepared by the incipient wetness impregnation method and their activities for ammonia decomposition in the presence of plasma were studied. The Fe-Ni bimetallic catalyst exhibited a better synergistic effect than the other three bimetallic catalysts. The effect of the Fe/Ni molar ratio on its catalytic activity was also investigated. A 6：4 Fe/Ni molar ratio resulted in the highest ammonia decomposition activity and stability. The catalysts were characterized by N2 adsorption- desorption, XRD, H2-TPR, and HRTEM. The characterization results indicated that NiFe204 with a spinel structure was formed in the optimal Fe-Ni bimetallic catalysts and this structure favors the reduction of Fe and Ni. In other words, it is easy to achieve the metallic state of active components for the Fe-Ni bimetallic catalysts, which could be the reason for the high catalytic activity of bimetallic catalysts for NH3 decomposition.