Composition engineered GNS/CNT Hybrid nanocomposites with enhanced thermal stability and tunable optical properties via one-step methane CVD

Abstract

Abstract Graphene nanosheet/carbon nanotube (GNS/CNT) hybrid nanocomposites were produced using a one-step methane CVD method, employing a Mo–Mg–Fe catalytic system. This facilitated the concurrent growth and integration of graphitic elements. The impact of the Mo/Mg ratio on structural development, oxide chemistry, defect density, and thermal stability was examined in detail. SAED, TEM, and SEM revealed the coexistence of wrinkled graphene sheets linked with CNTs, while EDS and STEM showed even C, O, Mg, Mo, and Fe distribution. Raman indicated low defects (I D /I G ≈ 0.14), I 2D /I G = 0.33, and A 2D /A G ≈ 0.43, which reveals that samples have common characteristics of few to multilayer graphene structures. FTIR reflected Mo/Mg-dependent oxide and surface chemistry, and UV–Vis revealed broad, enhanced optical absorption. TGA conducted in an inert atmosphere demonstrated remarkable enhanced thermal stability, characterized by negligible mass loss (2–6%) up to 1000 °C; this stability is ascribed to the formation of Mo-assisted carbides and the mitigation of Mg volatilization. The CVD method creates hybrids that are structurally low in defects. These hybrids show improved thermal stability and allow for the adjustment of their physical and chemical properties. As a result, these findings confirm that changing the catalyst’s composition is a useful way to design carbon nanohybrids with multiple functions.