Synthesis and Characterization of Niobium Carbide with Copper Addition Obtained Via Gas Solid Reaction

The use of niobium containing materials' has gained much attention of the scientific community in the late years due its various applications in diverse fields. NbC is a highly versatile material. Copper addition may alter several of its properties, such as morphology, crystal structure etc. as well as enhance its catalytic behavior. Nanostructured NbC with copper addition synthesis' presented here had the precursor [(NH4)3[NbO(C2O4)3]xH2O] as starting material, which was doped with Cu(NO3)2 at 5% and 10% (molar) ratios. Doped NbC was obtained via gas solid reaction in fixed bed reactor at lower temperature (980°C) and with shorter reaction time (2h) than traditional methods. Reaction products' were characterized by XRD, crystal sizes were estimated according to HWL method, and SEM, XRF, BET and laser particle size analysis were performed. XRD indicated the formation of NbC and Cu phases with cubic crystal structure of ~20nm. SEM showed slight morphological change upon increasing copper content, indicating a less porous structure, which is consistent with BET data (43.7m2/g for 5%Cu-NbC and 37m 2/g for the 10% Cu-NbC). Crystal size calculations showed that increasing dopant content particle sizes were also increased, probably due to the presence of the dopant, in some extent, in the crystal structure.近年来，含铌材料因其在多领域的广泛应用而受到科学界的高度关注。碳化铌（NbC）是一种用途极为广泛的材料。铜掺杂可改变其多项性能，如形貌、晶体结构等，同时还能提升其催化性能。本研究制备的铜掺杂纳米结构碳化铌，以[(NH₄)₃[NbO(C₂O₄)₃]·xH₂O]为前驱体原料，分别以5%和10%的摩尔比掺入硝酸铜（Cu(NO₃)₂）进行掺杂。相较于传统制备方法，本研究通过固定床反应器内的气固反应，在较低温度（980℃）和更短反应时间（2h）下得到了掺杂型碳化铌。采用X射线衍射（XRD）对反应产物进行表征，通过HWL法估算晶体尺寸，并辅以扫描电子显微镜（SEM）、X射线荧光光谱（XRF）、比表面积测试法（BET）以及激光粒度分析开展性能测试。XRD表征结果显示，产物形成了具有立方晶体结构的碳化铌与铜相，晶粒尺寸约为20nm。SEM观测结果表明，随着铜掺杂量的增加，产物形貌发生轻微变化，孔隙结构愈发致密，这与BET测试结果相符：5%铜掺杂碳化铌的比表面积为43.7m²/g，10%铜掺杂碳化铌则为37m²/g。晶体尺寸计算结果显示，随着掺杂剂含量的提升，晶粒尺寸也随之增大，这可能是因为掺杂剂在一定程度上进入了晶体结构之中。