Controllable adjustment of nickel accessibility on CeO2 by hard template for efficient hydrogen production via steam reforming of methane

The sol-gel method produces supported nickel catalysts possessing good stability. However, the catalysts are plagued by the issue of severe nickel embedment, which limits the accessibility and utilization efficiency of active sites. To address this issue, hard template (e.g., CNTs and SBA-15) was added during the sol-gel synthesis of Ni/CeO 2 , and subsequently removed to optimize the accessibility and stability of Ni nanoparticles on ceria. This approach effectively adjusts the embedment, exposure, deficiency and dispersion of Ni nanoparticles on ceria, thus endows Ni/CeO 2 with high activity, high H 2 selectivity and good stability. As regulated by SBA-15, the Ni/CeO 2 catalyst possesses high specific surface area (128.9 m 2 /g), abundant oxygen defects, large surface nickel content (5.39%), and small nickel particle size (4.58 nm). The optimized Ni/CeO 2 catalyst achieved a methane conversion of 82% at 650 °C, under a methane GHSV of 10000 mL h −1 ·g cat −1 and a water/methane ratio of 2. Moreover, this activity is well maintained for 100 h without any deactivation.