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• Ni/SiO 2 catalysts were prepared from aqueous Ni(NO 3) 2 solutions by the precipitation method using Na 2 SiO 3. • This is a simple but efficient method to prepare well-dispersed NiO on silica. • The prepared catalysts were active for two model reactions, benzene hydrogenation and CO methanation. Ni/SiO 2 catalysts with high Ni content were prepared from aqueous Ni(NO 3) 2 solutions by the precipitation method using Na 2 SiO 3 as a silica precursor and precipitant. This is a simple but efficient method to prepare well-dispersed NiO on silica, which can be further transformed to Ni/SiO 2 through an additional reduction process. Various techniques such as nitrogen physisorption, X-ray diffraction (XRD), temperature-programmed reduction with hydrogen (H 2 -TPR), hydrogen chemisorption, high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were employed to characterize the catalysts. The prepared catalysts were applied to two model reactions, benzene hydrogenation and CO methanation. The catalyst showed significantly enhanced performance for these reactions compared to core-shell Ni@SiO 2 catalysts and conventional Ni/SiO 2 catalysts prepared by wet impregnation. [ABSTRACT FROM AUTHOR]

• Core–shell Al@Al2O3 was used as the support in supported Ni catalysts. • The Al@Al2O3 is better than γ-Al2O3 to develop a highly efficient Ni-based catalyst. • The deposition–precipitation method outperforms the wet impregnation method. • Higher Ni dispersion resulted in better catalytic performance for CO methanation. • The higher density of medium basic sites increases the CO 2 methanation activity. Core–shell Al@Al 2 O 3 , which was obtained by hydrothermal surface oxidation of Al metal particles, was used as the support in supported Ni catalysts for CO and CO 2 methanation. The core–shell micro-structured support (Al@Al 2 O 3) helped develop a highly efficient Ni-based catalyst compared with conventional γ-Al 2 O 3 for these reactions. Moreover, the deposition–precipitation method was shown to outperform the wet impregnation method in the preparation of the active supported Ni catalysts. The catalysts were characterized using various techniques, namely, N 2 physisorption, H 2 chemisorption, CO 2 chemisorption, temperature-programmed reduction with H 2 , temperature-programmed desorption after CO 2 adsorption, X-ray diffraction, inductively coupled plasma-atomic emission spectroscopy, high-resolution transmission electron microscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy. Higher Ni dispersion when using Al@Al 2 O 3 as the support and the deposition–precipitation method resulted in better catalytic performance for CO methanation. Furthermore, the higher density of medium basic sites and enhanced CO 2 adsorption capacity observed for Ni/Al@Al 2 O 3 helped increase catalytic activity for CO 2 methanation. [ABSTRACT FROM AUTHOR]