Hydrogen production by sorption enhanced catalytic pyrolysis of lignin waste in presence of novel potassium stannate

Lignocellulosic waste stands out as an abundant and environmentally friendly feedstock to produce biofuels including renewable hydrogen. For the first time, potassium stannate dual functional material (DFM) was synthesised and assessed in the sorption enhanced pyrolysis of lignin waste and compared to zirconates DFMs by thermogravimetric analysis and in a packed bed reactor with online gas analysis. The results indicate that K₂SnO₃ presents a superior capacity in selectively producing hydrogen at 700 °C with 51 vol% of the gas produced being H₂ (45 g _H2/kg _Etek lignin) with and only 9 vol% CO₂, when a lignin: K₂SnO₃ ratio of 0.5:3 was used. The same DFM with a lignin: K₂SnO₃ ratio of 1:0.5 promoted the RWGS and Boudouard reactions converting the absorbed CO₂ and formed H₂ and char into CO at 900 °C. In summary, K₂SnO₃ is a promising catalyst to produce hydrogen from biomass pyrolysis-reforming.