Hydrogen production from cotton stalk over Ni-La catalysts supported on spent bleaching clay via hydrothermal gasification

Cotton stalk was gasified to produce H2 with Ni-La based catalysts in subcritical and supercritical water. Approximately 90% H2 yield was obtained under optimized conditions (360 degrees C, 0.5 g Ni-La catalyst loading, 0.5 g biomass and 10 min) by an orthogonal design with Ni-La/spent bleaching clay (SBC) materials. In addition, the H2 yield of rice and wheat straw increased by 41.5 and 39.5 times, respectively at optimized conditions. It was found that the activity of Ni-La materials supported on SBC ash and Al2O3 was similar, with H2 yields of 108.3% and 115.1% at 380 degrees C, respectively in 5 min. SBC ash provided a high specific surface area (94.4 m2/g) for the NiLa catalyst. La-promoted Ni/SBC (0.19 mmol/g) had a stronger acidity than Ni/SBC (0.16 mmol/g). Ni-La/SBC had a broad reduction peak, indicating the uniform dispersion of Ni on the support. Ni-La/SBC materials not only realized the reuse of SBC but also effectively promoted the hydrothermal gasification of agricultural wastes.

Automated summary

Cotton stalk can be effectively gasified to produce H2 using Ni-La based catalysts in subcritical and supercritical water. Optimized conditions can significantly increase the H2 yield, and the Ni-La/SBC materials not only realize the reuse of spent bleaching clay but also effectively promote the hydrothermal gasification of agricultural wastes.