Melamine-formaldehyde (MF) microspheres were prepared using acetic acid as the catalyst without aid of any surfactant, and were carbonized to obtain nitrogen-doped carbon microspheres. The effects on the microstructure of stirring time, acid amount and thickness of the layer of MF spheres spread in the crucible during carbonization, and the particle size and distribution of the MF and carbon microspheres were investigated by SEM, TEM, FTIR, TGA, XPS, nitrogen adsorption and elemental analysis. Results indicated that by increasing the stirring time from 1 min to 48 h, the median particle size of the MF microspheres increased rapidly in the first 10 min from 0.6 to 1.6 μm, levelled off from 1.6 to 1.7 μm between 10 and 120 min, then decreased slowly to 1.055 μm from 120 min to 24 h and then levelled off again from 1.055 to 1.047 μm between 24 and 48 h. The particle size became narrower and the surface smoother with increasing stirring time. Increasing the amount of acetic acid reduced the particle size, but broadened the size distribution and led to particle aggregation. The thermal stability and carbonization yield increased and the particle shrinkage during carbonization decreased with stirring time since the molecular weight of the polymers that formed the MF microspheres increased with stirring time. The carbonized samples produced using a thin spread layer have better sphericity and monodispersion than those from a thick and dense spread layer. Severe particle aggregation was found regardless of the carbonization temperature in the latter case. The carbon microspheres had lower nitrogen and oxygen, but higher carbon, contents with a longer stirring time, and nitrogen atoms were in the form of pyridinic N(N-6), pyrrolic-N(N-5) and quaternary-N/graphitic-N(N-4) nitrogen. The carbon microspheres had an inverse core-shell structure with a mesoporous shell and a dense carbon core.

在不使用任何表面活性剂的情况下，使用乙酸作为催化剂制备三聚氰胺-甲醛（MF）微球，并将其碳化以获得氮掺杂碳微球。用SEM，TEM，FTIR，TGA，XPS研究了碳化过程中搅拌时间，酸度和在坩埚中扩散的MF球层的厚度对微观结构的影响，以及MF和碳微球的粒径和分布。 ，氮吸附和元素分析。结果表明，通过将搅拌时间从1分钟增加到48小时，MF微球的中值粒径在前10分钟迅速从0.6微米增加到1.6微米，在10到120分钟之间从1.6微米增加到1.7微米，然后从120分钟到24小时缓慢减小到1.055μm，然后从1.055减小到1。24至48小时之间为047μm。随着搅拌时间的增加，粒度变窄并且表面更光滑。增加乙酸的量会减小粒径，但会扩大粒径分布并导致颗粒聚集。由于形成MF微球的聚合物的分子量随着搅拌时间而增加，因此随着搅拌时间的增加，热稳定性和碳化产率增加并且碳化期间的颗粒收缩减小。与薄而密集的扩展层相比，使用薄扩展层生成的碳化样品具有更好的球形度和单分散性。在后一种情况下，无论碳化温度如何，都发现严重的颗粒聚集。碳微球的氮和氧含量较低，但碳含量较高，搅拌时间较长，氮原子的形式为吡啶N（N-6），吡咯N（N-5）和季N /石墨N（N-4）氮。碳微球具有反向的核-壳结构，具有中孔壳和致密的碳核。