Magnetic nanomaterials show promising applications in heterogeneous catalysis because of their ease of separation and good reusability. The magnetization saturation values of magnetic nanoparticles mainly depend on finite-size and surface effects. For small magnetic nanoparticles, the formation of domain walls provides a high energy state and the particles aggregate easily in clusters or clumps. To avoid agglomeration, magnetic nanoparticles can be coated with different shells (e.g., silica, carbon, metal, metal oxide, and polymer) to isolate them from external environments. Because of high surface area of magnetic nanoparticles, many active species can be supported on the surface to enhance the catalytic activity. This review focuses on recent developments of various magnetic nanomaterials in heterogeneous catalysis, including hydrogenation reaction, Suzuki–Miyaura reaction, oxidation reaction, chiral catalysis, enzyme catalysis, photocatalysis, electrocatalysis, and photoelectrochemical catalysis. Different synthesis strategies for magnetic nanomaterials are summarized. The active sites, stability, and catalytic mechanisms are discussed. Challenges and perspectives for magnetic nanomaterials in commercial applications are documented.

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An investigation on electronic, elastic, and optical properties of XC ͑X = Si, Ge, and Sn͒ under high pressure has been conducted using first-principles calculations based on density functional theory with the plane wave basis set as implemented in the CASTEP code. Our results demonstrate that the sequence of the pressure-induced structure transition of these compounds is from zincblende-type ͑B3͒ to NaCl-type ͑B1͒ structure. The calculated lattice constants and transition pressures are reported, which are in good agreement with the available experimental results and the previous theoretical data. The elastic constants and anisotropy as a function of pressure are presented. These results suggest technological applications of such materials in extreme environments. Debye temperatures of B3-SnC and B1-SnC are determined for the first time.

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