Steam reforming of monohydric alcohols and polyalcohols: Influence of single or multiple hydroxyl group(s) on nature of the coke

[Display omitted] •–OH in ethanol, glycol, 1-propanol and glycerol impacts their reactivity in reforming.•Ethanol/1-propanol reforming produces more CHx/CC but less OH than in glycol/glycerol.•Number of hydroxyl group of alcohols impacts coking tendency and nature of coke.•Coke of glycol/glycerol is more aliphatic with higher impact on catalytic activity.•Carbon nanotubes from reforming of glycol/glycerol have thick wall and rough surface. Alcohols like ethanol and glycerol have been extensively investigated as potential feedstock for on-site hydrogen production by steam reforming. The varied number of hydroxyl group in the alcohols inevitably affects the reaction intermediates generated and eventually properties of coke formed. In this study, four alcohols (ethanol, ethylene glycol, 1-propanol and glycerol) with the single or multiple hydroxyl groups were steam reformed, focusing on the influence of the hydroxyl group on the properties of the coke. The research results showed that steam reforming of ethanol and glycerol produced more coke than that in steam reforming of 1-propanol or ethylene glycol, while the Ni/SBA-15 catalyst deactivated to a higher extent in steam reforming of ethylene glycol or glycerol with multiple hydroxyl group, due to the coke of varied properties. The coke produced by steam reforming of ethanol and 1-propanol contained more defective structures but more aromatic. However, the generated coke from the steam reforming of ethylene glycol and glycerol had more aliphatic structures, especially in that from ethylene glycol. On the other hand, the carbon nanotubes formed by the steam reforming of ethanol or 1-propanol had thin wall thickness and smooth surface, while that in steam reforming of ethylene glycol and glycerol had thick wall and very rough surface, resulting from the distinct reaction intermediates formed.