An Extensive Study of the Production of Hydrogen by Cellulose and Lignin Pyrolysis Using Rhenium-Based Catalysts

The use of rhenium-based catalysts (Re2C, Re3B, ReB2, and ReS2) obtained by mechanosynthesis in the pyrolysis of cellulose and lignin from 500 to 800 °C using 10 and 20 wt.% of catalysts is reported. The mechanosynthesis of ReS2 has been reported for the first time. The catalytic pyrolysis of cellulose resulted in maximum H2 production at 800 °C and 10 wt.% catalyst, with 44% H2 yield using a Re3B catalyst. In contrast, lignin catalytic pyrolysis also showed maximum production under the same conditions, with an 86.1% H2 yield using the NiO/SiO2 catalyst; however, the catalyst did not drastically enhance H2 production. H2 formation by cellulose pyrolysis is a thermocatalytic process, whereas lignin pyrolysis is an entirely thermic process. A reaction mechanism was proposed to explain the H2 formation by both catalytic cellulose and lignin pyrolysis.