Tuning Y-Mg Supports for Improved Ni-Catalyzed NH3 Decomposition: Structural Modulation and Mechanistic Insights

en This link goes to a English section zh This link goes to a Chinese section Catalytic NH 3 decomposition has garnered substantial attention for hydrogen transformation and storage. Ni-based catalysts continue to suffer from limited thermal stability and suboptimal low-temperature activity, largely attributed to an incomplete understanding of the structure-activity relationships and reaction mechanisms governing their performance. In this study, we designed and constructed a novel Y-Mg bimetallic oxide support system to synergistically modulate the properties of Ni-based catalysts for NH 3 decomposition. Unlike conventional Ni/MgO or Ni/Y 2 O 3 , the precisely tuned Y/Mg ratio in the 20Ni/YMg 8 catalyst creates a unique interface that couples the structural and electronic advantages of both components. A series of Ni-based catalysts with varying Y/Mg ratios was synthesized, and the 20Ni/YMg 8 catalyst with a 1:8 ratio of Y: Mg achieved a hydrogen production rate of 29.77 mmol g cat −1 min −1 at 600°C. Characterizations revealed that Mg incorporation primarily increased surface area and refined Ni dispersion, whereas Y enhanced reducibility and active metal distribution. More importantly, their synergy optimally tailors the electronic structure of Ni and the distribution of basic sites, which collectively promote *NH 2 formation and accelerate N 2 desorption—the rate-determining step. Mechanistic studies confirmed that the optimized catalyst promoted *NH 2 formation and accelerated N 2 evolution, indicating enhanced NH 2 activation and dehydrogenation. This study presents a rational design approach of bimetallic supports to modulate structural and surface properties, offering valuable insights into the development of efficient and stable Ni-based catalysts for ammonia decomposition. 摘要 en This link goes to a English section zh This link goes to a Chinese section 氨催化分解因其在氢能转化与储存方面的潜力而备受关注。镍基催化剂仍面临热稳定性不足和低温活性欠佳的挑战,这主要归因于对其构效关系及反应机理的认识尚不完善。本研究中,我们设计并构建了一种新型的Y-Mg双金属氧化物载体体系,以协同调控镍基催化剂的氨分解性能。与传统的Ni/MgO或Ni/Y 2 O 3 催化剂不同,20Ni/YMg 8 催化剂中精确调控的Y/Mg比例形成了一种独特的界面,耦合了两种组分的结构优势与电子优势。通过合成一系列不同Y/Mg比例的镍基催化剂,我们发现Y:Mg比例为1:8的20Ni/YMg 8 催化剂在600°C时达到了29.77 mmol g cat −1 min −1 的产氢速率。表征结果显示,Mg的引入主要增加了比表面积并优化了Ni的分散性,而Y则增强了还原性和活性金属分布。更重要的是,二者的协同作用精准调控了Ni的电子结构和碱性位点分布,共同促进了NH 2 的形成并加速了N 2 脱附(速率控制步骤)。机理研究证实,优化后的催化剂促进了 NH 2 的形成并加快了N 2 的生成,表明NH 2 的活化和脱氢过程得到增强。本研究为双金属载体的理性设计以调控结构及表面性质提供了新思路,为开发高效稳定的氨分解镍基催化剂提供了重要见解。