fig6 shows the spectrum of humic acid reduced with hydrazine and then pyrolyzed at 370 u00b0 c i e graphenol it can be seen in fig6 that most of the carboxylic acid groups have been eliminated and the largest peak is c u2014 oh peak the ir spectrum not shown contains a large peak at around 3600 cm u2212 1 which is characteristic of oh the hydrogenation catalysts that have been tested so far include raney nickel copper chromium oxide and ruthenium oxide it appears that all of these catalysts work equally well but any hydrogenation catalysts can be employed in the process an alternative method of producing graphene that has also been discovered involves first extracting leonardite lignite or peat with a strong base or dimethylformamide to create a dispersion of humic acid coating a substrate to form a thin film of the humic acid drying the film pyrolysis of the film under argon or argon hydrogen at 400 to 800 u00b0 c this process forms a thin layer of graphene on the substrate in this process one possible base is ammonium hydroxide dissolved in a water alcohol mixture the alcohol minimizes the u201c coffee stain u201d effect typically seen with just water solutions some alcohols known to be effective at this stage are methanol ethanol and propanol the ammonium hydroxide is advantageous as a base because in the drying step it can be evaporated away possible substrates are copper or nickel foils but quartz mica or other suitable materials may also be used the graphenol particles are dispersible in polar liquids such as water or small alcohols it is advantages to have functional graphenes that are dispersible in nonpolar organic.