Temperature-Programmed Alkaline Thermal Treatment of Lignocellulosic Biomass to Produce Fractionated Hydrogen with High Production Capacity

H2 production is severely limited by inefficient conversion of feedstock, inevitable char formation, and methanation reactions aggravated by the slow heating rate during conventional alkaline thermal treatment (ATT) of biomass. Herein, a temperature-programmed alkaline thermal treatment (TP-ATT) incorporating dehydrogenation below 250 °C and rapid alkalinization at 600 °C is developed to produce fractionated H2 with a high production capacity of 46.06 mmol·g–1 of cellulose. The H2 produced via NaOH-promoted dehydrogenation exhibits a high purity of 98%. Optimized TP-ATT achieves complete conversions of cellulose and hemicellulose, and the H2 productions are 46, 24, and 89% higher than those of conventional ATT from cellulose, hemicellulose, and lignin, respectively. Fast heating and steam-promoted alkalinization reactions are essential for the efficient conversion of char with high H2 production. TP-ATT of cellulose realizes a 98.14% energy recovery of both H2 and CH4. The TP-ATT technology is applicable to different real biomass with approximately 43% higher H2 production than conventional ATT.