Hydroxyapatite supported Ni and La2O3 boost methane-enriched gas production from pyrolysis-steam reforming of corn stalk

Abstract

The production of methane-enriched gas via thermo-chemical process is an important approach for biomass valorization. However, current pyrolysis processes generally give low yield of value-added gas product. Herein, a series of Ni-based materials with hydroxyapatite (HAP) and titanium silicate (TS) as supports were prepared and investigated as catalysts to boost CH₄ production from pyrolysis-steam reforming of corn stalk. The surface element composition, chemical state and crystal structure of materials were characterized by transmission electron microscope (TEM), N₂ adsorption-desorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The expected loading of Ni, La and Ce were successfully loaded onto HAP via simple impregnation method, while the loading of active metals on TS is finite. Ni-5La₂O₃/HAP exhibited the best catalytic activity for pyrolysis-steam reforming of corn stalk, attaining CH₄ yield (19.41 mmol/g) that is 89.9 % and 46.2 % higher than control experiment and Ni-5CeO₂/MCM-41, indicating that loading high-density Ni and La species onto HAP supports can greatly boost the CH₄ formation. However, the catalysts lost activity obviously during recycling experiment probably due to carbon accumulation.