Boosting turquoise hydrogen and carbon nanotube production catalytic methane decomposition: influence of active metal ratios in Fe5-Co-Zn/γ-AlO nanocatalysts.

The present study reports the synthesis of a series of nanocatalysts (NCs) comprising iron (Fe), cobalt (Co), and zinc (Zn) supported on γ-AlO nanopowder (Fe5-Co-Zn/γ-AlO) by tuning the metals stoichiometric ratio using a facile co-precipitation approach. The powder X-ray diffraction patterns and Raman spectra revealed that the freshly synthesized Fe5-Co-Zn/γ-AlO is composed of hexagonal FeO, cubic CoO, and hexagonal ZnO phases. The NCs exhibited efficient performance in CH decomposition, yielding turquoise hydrogen (H) and carbon nanotubes (CNTs) as solid carbon by-products. The active metals consisted of 50% Fe, 5% Co, and 15% Zn as Fe5Co0.5Zn1.5 given a maximum CH conversion of 90% and an H yield of 92.2%, which are considerably higher than those of many other previously reported NCs. The structural characteristics of the spent NCs (S-Fe5Co2Zn0 to S-Fe5Co0Zn2) were examined, showing variation in the growth and quality of CNT. Moreover, the electron microscopy micrographs suggested that the CNTs growth plausibly followed the base-growth model. The CNTs are also effectively isolated from spent NCs. This study paves the way for a streamlined approach to designing and unravelling the intricate distribution of active metals on suitable supports, offering deeper insights into optimizing CH decomposition into H and high-quality CNTs.