Plasma-catalytic ammonia synthesis has garnered significant attention due to its potentialfor reducing energy consumption and mitigating environmental impact, emerging as a promisingalternative to traditional thermal catalytic ammonia synthesis processes. Developing efficient catalyststo enhance the synergy between plasma and catalytic materials remains a key challenge. This studyEnergy Environmental Protectionexperimentally investigated a series of supported SBA-15 catalysts (M/SBA-15, M = 5Fe, 5Co, 5Ni,10Ni, and 15Ni) to examine the process of plasma-enhanced ammonia synthesis. The initialcharacterization results indicated that the active metal species in all catalysts were present as metallicelements and oxides, both on the catalyst surface and within the pores, exhibiting uniform dispersion.Activity tests revealed that catalytic performance was not correlated with the specific surface area of thecatalysts; rather, the inherent ammonia synthesis properties of the active metal species had a moresignificant impact. Notably, Ni-based catalysts exhibited superior catalytic activity compared to thosebased on Fe and Co. Further investigation into the ammonia synthesis activity of catalysts with varyingNi loadings revealed a volcano-shaped curve in plasma-assisted ammonia concentration, which initiallyincreased and then decreased with increased Ni loading. Specifically, increasing the Ni loading from 5%to 10% improved ammonia synthesis performance by 8.0%, while further increasing the Ni loading to15% led to a 3.3% decrease in performance. This relationship implied that a critical Ni loadingthreshold existed, above which excessive Ni loading could damage the catalyst's pore structure or causesurface poisoning. Subsequently, the discharge characteristics of the 10Ni/SBA-15 catalyst, whichexhibited the highest ammonia synthesis performance, were analyzed. The results revealed a transitionin discharge mode from filamentary discharge to a combination of filamentary and surface discharge, incontrast to an empty tube. This transition led to a more uniform and stable discharge state, with higheraverage current values within the clusters. The enhanced discharge state promoted the generation ofmore high-energy electrons and excited-state species, such as , , and NH (x=1, 2), which areessential for ammonia synthesis, thereby significantly improving ammonia production. Stability testsdemonstrated that catalyst activity rapidly decreased during the first 180 minutes, followed bystabilization, emphasizing the importance of preserving the catalyst's pore structure for prolongedcatalytic activity. Finally, the plasma-assisted ammonia synthesis performance of the catalyst wasevaluated for ammonia concentration and energy yield. The evaluation results indicated that, incomparison to related cutting-edge research, this study achieved ammonia concentrations as high as9 927 mg/m³ and an energy yield of 0.88 g/(kW·h) with the 10Ni/SBA-15 catalyst, showcasingsignificant competitiveness. These findings contribute to understanding the plasma catalytic process andprovide new insights into the design of efficient catalysts for plasma-assisted ammonia synthesis.