Hydrogen generation from simulated biomass pyrolysis tail gas on Ni–CeO2–Al2O3 catalysts

Abstract

The pyrolysis of biomass inevitably produces gaseous products, known as tail gases, which should be considered as a renewable resource to increase the value of the pyrolysis process. The conversion of simulated cotton stalk pyrolysis gases into hydrogen was studied on a series of Ni–Ce–Al catalysts with various Ce/Al ratios synthesized via one-pot urea hydrolysis. The catalysts were evaluated in a fixed-bed reactor at 600 °C. The correlation between catalytic activity and physicochemical properties was analyzed using ICP-OES, BET, XRD, H₂-TPR, CO₂-TPD, XPS, TEM, and TGA. Among the catalysts tested, Ni–0.4Ce–Al exhibited excellent activity and stability, where the CH₄ conversion rate, CO conversion rate, and H₂ production rate reached 84.5%, 79.1%, and 82.1%, respectively. This enhanced performance was attributed to the improved reducibility, more weak basic sites, and high dispersion of active species. In addition, the strong interaction between Ni and CeO₂ effectively prevents metal sintering and provides oxygen vacancies through the Ce⁴⁺–Ce³⁺ pathway to enhance the anti-carbon deposition ability, thereby improving the overall stability of the catalyst.