Although the nickel-based catalyst is able to exhibit comparative catalytic activity to noble metal for methyl acrylate hydrogenation, it requires strict reaction condition, which can be improved by regulation of coordination environment. In this study, we constructed a kind of Ni single-atom coordinated with N and S (Ni-NSC) through the pyrolysis of organic Ni-based precursors at 600 °C. The existence and fine structure of Ni single-atom were confirmed by the spherical electron microscopic observation in combination with the X-ray absorption spectroscopy (XAS) characterization. In addition, the catalytic hydrogenation assessment suggested that the as-prepared Ni-NSC catalyst exhibited higher activity and stability than the Ni/NSC supported catalyst prepared by incipient wetness impregnation method. This remarkable catalytic activity was due to the high dispersion and density of Ni single-atom and weak adsorption energy of intermediates on these Ni sites.

MoS₂ nanoflowers are favored for their potential in the production of elemental sulfur due to abundant surface area and good catalytic performance for reducing SO₂. A novel synthetic strategy of porous Al₂O₃ supported on the MoS₂ with nanoflower structure was proposed. The effects of preparation concentration, calcination atmosphere, and Al₂O₃ contents on the growth of catalysts with nanoflower structure were systematically studied via X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET). The surface area was increased to 295.502 m²/g and the amount of Lewis acid on the surface of the Al₂O₃/MoS₂ catalyst was increased by adjusting the ratio of Al/Mo. The porous and nanoflower structures of Al₂O₃/MoS₂ catalysts promoted the sulfur selectivity without inhibiting the catalytic performance of MoS₂. The conversion of SO₂ and the selectivity of sulfur were 100% and 92% after 100 h life evaluation.