Higher Alcohol and Oxygenate Synthesis from Synthesis Gas and Ethanol over Supported K-(Co)MoS2 Catalysts: Effect of Novel Ni-Containing Carbon Nanofiber Supports Formed as Byproducts from Methane Decomposition

The supports nature employed greatly affects the catalytic activities and physicochemical characteristics of catalysts. In the present investigation, after the catalytic decomposition of methane using 82Ni-8Cu/Al2O3 catalyst, an inactive catalyst containing a carbon nanofiber byproduct has been studied as a support for synthesis of higher alcohols and other oxygenates from syngas and ethanol conversion, respectively, over a K-modified Co-promoted MoS2 catalyst. The catalytic results have been compared with those of catalysts supported on Al2O3, carbon-coated alumina, and two types of fabric-activated carbon (NWA and AST). Besides, an unprompted (K)-MoS2 catalyst supported on CNF-82Ni-8Cu/Al2O3 (CNFS) has been tested to investigate the mobility probability of Ni atoms from support to the KMoS2 active phase. N2 adsorption-desorption, X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to analyze the sulfided catalysts. On comparing CNFS-supported catalysts to alumina-based supports and fabric-activated carbons, the CNFS-supported catalysts demonstrated the highest ability to resist hydrogenation and water-gas shift reactions. This was due to the highest average stacking number and average slab length, which were likely caused by the minimal interaction between the active phase and CNFS support. As a result, it causes the atoms of potassium and cobalt to develop electronic states that are favorable for the higher synthesis of alcohols. KMoS2/CNFS has demonstrated the best selectivity toward ethanol and total liquid yield. The order of supported sulfided catalysts for synthesizing other oxygenates from ethanol conversion decreases as follows: KMoS2/CNFS > KCoMoS2/AST > KCoMoS2/NWA ≥ KCoMoS2/CNFS > KCoMoS2/CCA ≥ KCoMoS2/Al2O3. For the first time, the possibility of dynamics of nickel ions from support to the active phase has been proven. © 2024 American Chemical Society