A series of bimetallic CoMo/MgO catalysts with different total metal contents from 10 up to 60 wt% and a fixed Co/Mo weight ratio of 4/1 were prepared and employed for the first time to transform real low-density polyethylene (LDPE) waste into hydrogen and carbon nanomaterials through a two-stage process. The waste was thermally cracked at 500 °C to non-condensable gases which then decomposed over CoMo/MgO catalysts at 700 °C to obtain the desired products. Both fresh and spent CoMo/MgO catalysts were characterized by XRD, H₂-TPR, FTIR, Raman, BET, TEM, and TGA techniques. The results showed that the catalytic activity and stability were increased with the successive increase of CoMo content up to 40 wt%. Both 30CoMo/MgO and 40CoMo/MgO catalysts exhibited higher catalytic activity where more than 90% H₂ yield was obtained. This behavior could be attributed to the excessive formation of different types of mixed oxide species such as MgCoO_x, CoMoO_x and MgMoO_x as shown from XRD, TPR and Raman results. In fact, the presence of these species enhances the dispersion and stabilization of Co and Mo particles in the catalyst matrix, resulting in improved catalyst performance. TEM, Raman spectra, and TGA results showed that high-quality CNMs with various structures such as regular, bamboo, cup stacked carbon nanotubes were deposited over all CoMo/MgO catalysts depending on the CoMo content.

制备了一系列总金属含量从 10 到 60 wt% 且固定 Co/Mo 重量比为 4/1 的双金属 CoMo/MgO 催化剂，并首次用于转化真正的低密度聚乙烯（LDPE）废物通过两阶段过程转化为氢和碳纳米材料。废物在 500 °C 下热裂解成不可冷凝的气体，然后在 700 °C 下在 CoMo/MgO 催化剂上分解以获得所需的产品。新鲜和废 CoMo/MgO 催化剂均通过 XRD、H ₂ -TPR、FTIR、拉曼、BET、TEM 和 TGA 技术进行表征。结果表明，随着 CoMo 含量的连续增加至 40 wt%，催化活性和稳定性增加。30CoMo/MgO 和 40CoMo/MgO 催化剂均表现出更高的催化活性，其中超过 90%的 H获得₂收率。如XRD、TPR 和拉曼结果所示，这种行为可归因于不同类型的混合氧化物物种如MgCoO _x、CoMoO _x和MgMoO _x的过度形成。事实上，这些物质的存在增强了 Co 和 Mo 颗粒在催化剂基质中的分散性和稳定性，从而提高了催化剂性能。TEM、拉曼光谱和 TGA 结果表明，根据 CoMo 含量，在所有 CoMo/MgO 催化剂上沉积了具有各种结构的高质量 CNM，如规则、竹子、杯状堆叠碳纳米管。