Ni-MoO2 heterostructure encapsulated in mesoporous silica microtubes: a structured hydrogenation catalyst with enhanced activity for reduction of 4-nitrophenol

Metallic Ni catalysts often suffer from serious aggregation and poor stability during the process of catalysis. In this work, core-shell nanostructures with nanosized MoO2-Ni nanoparticles (NPs) and mesoporous SiO2(mSiO2) shells were well designed to address these issues. The Ni-MoO2 hybrid cores were converted from hierarchical NiMoO4 microtubes inside the SiO2 shell through carbonization treatment to remove the hexadecyl trimethyl ammonium bromide (CTAB) template under the protection of a nitrogen atmosphere. The mesoporous SiO2 shells in Ni-MoO2@mSiO2 nanoreactors prevented the agglomeration/sintering of Ni NPs, while allowing the mass diffusion of small molecules. Owing to the high catalytic performance of Ni-MoO2 cores, good protection of mesoporous silica, and the unique sandwich-like structure, the obtained Ni-MoO2@mSiO2 nanoreactors showed tremendous improvement in catalytic activity and stability.