Ni-Mg-Al类水滑石衍生镍基催化剂的制备及其氨分解性能  

Supported Ni Catalysts from Ni-Mg-Al Hydrotalcite-like Compounds:Preparation and Catalytic Performance for Ammonia Decomposition

作　　者：连敏丽 苏佳欣 黄鸿杨 嵇玉寅 邓海帆 张彤 陈崇启 李达林[1] LIAN Minli;SU Jiaxin;HUANG Hongyang;JI Yuyin;DENG Haifan;ZHANG Tong;CHEN Chongqi;LI Dalin(National Engineering Research Center of Chemical Fertilizer Catalyst,College of Chemical Engineering,Fuzhou University,Fuzhou 350002,China)

机构地区：[1]福州大学化工学院,化肥催化剂国家工程研究中心,福州350002

出　　处：《无机材料学报》2025年第1期53-60,共8页Journal of Inorganic Materials

基　　金：国家重点研发计划(2022YFB4002401);国家自然科学基金(22378070)。

摘　　要：氨分解作为一种很有前景的现场制氢技术,关键在于开发出廉价、高性能的催化剂。本研究通过共沉淀法合成系列Ni_(x)Mg_(75–x)Al_(25)类水滑石化合物(HTlc)作为前驱体,经过焙烧和还原处理制备负载型高分散Ni/Mg(Al)O催化剂并用于氨分解制氢,采用不同研究手段对样品进行了表征,考察了Ni含量和氨还原对催化性能的影响。结果显示,HTlc前驱体经过焙烧分解形成Mg(Ni,Al)O固溶体,Ni物种与载体之间存在较强的相互作用,经750℃氨还原得到高分散Ni金属纳米颗粒,其平均晶粒尺寸为5.9~7.7 nm。质谱分析表明,氨还原过程中无氮氧化物(NOx)生成,同时750℃氨还原与氢还原催化剂的活性相当,说明氨是一种合适的还原气。催化剂活性随着Ni含量和还原温度升高而增加。其中,750℃氨还原Ni_(20)Mg_(55)Al_(25)催化剂在30000 m L·g^(–1)cat·h^(–1)、600℃下的氨转化率为98%,且在100 h反应过程中转化率保持不变,Ni金属无明显烧结现象,催化剂表现出良好的活性、稳定性和抗烧结性能。Ammonia decomposition is a promising approach for on-site hydrogen generation for fuel cells,and the development of a cost-effective and efficient catalyst is highly desired.In this study,a series of Ni_(x)Mg_(75–x)Al_(25) hydrotalcite-like compounds(HTlc)with different Ni contents were synthesized by co-precipitation,followed by calcination and reduction treatments.Influences of Ni content and ammonia reduction on the catalytic performance for ammonia decomposition were investigated.The characterization results of the as-prepared samples showed that HTlc was decomposed into Mg(Ni,Al)O solid solution by calcination,which displayed a strong interaction between Ni species and support,while upon reduction with ammonia at 750℃,well-dispersed Ni metal nanoparticles with an average crystallite size range of 5.9–7.7 nm were formed.No nitrogen oxides(NOx)were produced during the NH3 reduction process as indicated by mass spectrometry analysis,and the catalyst reduced with ammonia showed comparable activity with that reduced with hydrogen,suggesting that ammonia can be used as a reductant gas.The catalyst activity increased with the increase of Ni content and reduction temperature.Among the catalysts,the Ni_(20)Mg_(55)Al_(25) catalyst reduced with ammonia at 750℃ showed the best activity,which afforded 98% ammonia conversion at 600℃ at a space velocity of 30000 mL·gcat^(–1)·h^(–1),and no evident deactivation was observed during a 100 h test,demonstrating good activity,stability,and sintering resistance.

关 键 词：制氢 氨分解 镍催化剂 类水滑石化合物 

分 类 号：O643[理学—物理化学]