Ni-MCM-41 nanocomposites were prepared by direct hydrothermal synthesis with different Ni contents. Various characterization techniques were conducted in order to study the properties of the materials. H-2 storage capacity and degradation of atrazine by heterogeneous photo-Fenton-like process were studied. The results indicated that the structural, chemical, adsorption and catalytic properties of the resulting materials strongly depend on the hydrothermal treatment days and the nickel content. The increase in the Si/Ni molar ratio leads to higher presence of nickel oxide and increment in hydrothermal treatment days favours the Ni incorporation inside mesoporous walls, decreasing the accessibility to the active sites.