Industrial needle-coke samples from different producers are investigated by X‑ray diffraction and scanning electron microscopy. Their structural parameters L a and L care determined, and...

Hydrogen production from biogas over alumina-supported Ce_1−xNi_xO_2−x catalysts was studied in a temperature range of 600–850 °C with an initial gas composition of CH₄/CO₂/H₂O of 1/0.8/0.4. To achieve a high and stable hydrogen yield, highly dispersed Ni catalysts were prepared through the exsolution approach. A solid solution of Ce_1−xNi_xO_2−x was firstly formed on the surface of Al₂O₃ and then activated in H₂/Ar at 800 °C. The genesis and properties of the Ce_1−xNi_xO_2−x/Al₂O₃ catalysts were established using X-ray fluorescence analysis, thermal analysis, N₂ adsorption, ex situ and in situ X-ray diffraction, Raman spectroscopy, electron microscopy, EDX analysis, and temperature-programmed hydrogen reduction. The performance of Ce_1−xNi_xO_2−x/Al₂O₃ catalysts in biogas conversion was tuned by regulation of the dispersion and reducibility of the active component through variation of content (5–20 wt.%) and composition (x = 0.2, 0.5, 0.8) of Ce_1−xNi_xO_2−x as well as the mode of its loading (co-impregnation (CI), citrate sol–gel method (SG)). For the 20 wt.% Ce_1−xNi_xO_2−x/Al₂O₃ catalyst, the rate of the coke formation decreased by a factor of 10 as x increased from 0.2 to 0.8. The optimal catalyst composition (20 wt.% Ce_0.2Ni_0.8O_1.8/80 wt.% Al₂O₃) and preparation mode (citrate sol–gel method) were determined. At 850 °C, the 20 wt.% Ce_0.2Ni_0.8O_1.8/Al₂O₃-SG catalyst provides 100% hydrogen yield at full CH₄ conversion and 85% CO₂ utilization.

The possibility of producing hexane-insoluble asphaltenes from a toluene solution of mid-temperature coal pitch is demonstrated. The topography, morphology, and structure of films consisting of...

The functional-group composition and structure of hexane-insoluble asphaltenes from coal pitch are studied. The methods employed are chemical (elemental) a

The thermal-destruction products of hexane-insoluble asphaltenes from coal pitch and petroleum asphaltenes are compared. The volatile thermal-decomposition products of the asphaltenes are...

Samples of baked low-temperature and needle coke are compared by X-ray phase analysis, X-ray structural analysis, analytical scanning electron microscopy,