Influence of Ni Precursors on the Structure, Performance, and Carbon Deposition of Ni-Al(2)O(3) Catalysts for CO Methanation

[Image: see text] Three Ni-Al(2)O(3) catalysts were prepared, in planetary ball-milling machine, by the mechanochemical method with Al(NO(3))(3)·9H(2)O as the aluminum precursor, (NH(4))(2)CO(3) as the precipitant, and Ni(NO(3))(2)·6H(2)O, NiCl(2)·6H(2)O, and Ni(CH(3)COO)(2)·4H(2)O as nickel precursors (the corresponding catalysts were labeled as Ni-NO, Ni-Cl, and Ni-Ac). The prepared catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (H(2)-TPR), and N(2) adsorption–desorption technologies, and CO methanation performance evaluation was carried out for the catalysts. Results showed that the catalyst with Ni(NO(3))(2)·6H(2)O as the precursor presented good Ni dispersibility and a small Ni grain size of 6.80 nm. CO conversion, CH(4) selectivity, and yield of the catalyst were as high as 78.8, 87.9, and 69.8%, respectively. Carbon deposition analysis from temperature-programmed hydrogenation (TPH) characterization showed that the H(2) consumption peak area of the three samples followed the order: Ni-NO (2886.66 au) < Ni-Cl (4389.97 au) < Ni-Ac (5721.65 au), indicating that the Ni-NO catalyst showed higher resistance to carbon deposition, which might be due to its small Ni grain size.