Unravelling the interfacial interaction in mesoporous SiO@nickel phyllosilicate/TiO core-shell nanostructures for photocatalytic activity.

Core-shell based nanostructures are attractive candidates for photocatalysis owing to their tunable physicochemical properties, their interfacial contact effects, and their efficacy in charge-carrier separation. This study reports, for the first time, on the synthesis of mesoporous silica@nickel phyllosilicate/titania (mSiO@NiPS/TiO) core-shell nanostructures. The TEM results showed that the mSiO@NiPS composite has a core-shell nanostructure with a unique flake-like shell morphology. XPS analysis revealed the successful formation of 1:1 nickel phyllosilicate on the SiO surface. The addition of TiO to the mSiO@NiPS yielded the mSiO@NiPS/TiO composite. The bandgap energy of mSiO@NiPS and of mSiO@NiPS/TiO were estimated to be 2.05 and 2.68 eV, respectively, indicating the role of titania in tuning the optoelectronic properties of the SiO@nickel phyllosilicate. As a proof of concept, the core-shell nanostructures were used as photocatalysts for the degradation of methyl violet dye and the degradation efficiencies were found to be 72% and 99% for the mSiO@NiPS and the mSiO@NiPS/TiO nanostructures, respectively. Furthermore, a recyclability test revealed good stability and recyclability of the mSiO@NiPS/TiO photocatalyst with a degradation efficacy of 93% after three cycles. The porous flake-like morphology of the nickel phyllosilicate acted as a suitable support for the TiO nanoparticles. Further, a coating of TiO on the mSiO@NiPS surface greatly affected the surface features and optoelectronic properties of the core-shell nanostructure and yielded superior photocatalytic properties.