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

Cotton stalk was gasified to produce H 2 with Ni-La based catalysts in subcritical and supercritical water. Approximately 90% H 2 yield was obtained under optimized conditions (360 °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 H 2 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 Al 2 O 3 was similar, with H 2 yields of 108.3% and 115.1% at 380 °C, respectively in 5 min. SBC ash provided a high specific surface area (94.4 m 2 /g) for the Ni-La 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 .