Photocatalytic splitting of seawater effected by (Ni-ZnO)@C nanoreactors

Novel photocatalysts i.e., metallic nickel and zinc oxide nanoparticles embedded in the carbon-shell ((Ni-ZnO)@C) have been used for photocatalytic splitting of seawater to generate H₂. The (Ni-ZnO)@C core-shell nanoparticles having the Zn/Ni ratios of 0-3 were prepared by carbonization of Ni²⁺- and Zn²⁺-β-cyclodextrin at 673K for 2h. To increase the collision frequency of water and photoactive sites within the carbon-shell, Ni and ZnO are partially etched from the (Ni-ZnO)@C core-shell to form yolk-shell nanoparticles with a H₂SO₄ solution (2N). By X-ray diffraction spectroscopy, mainly Ni and ZnO crystallites are observed in the core- and yolk-shell nanoparticles. The sizes of the Ni and ZnO in the (Ni-ZnO)>C nanoreactors are between 7 and 23nm in diameters determined by TEM and small angel scattering spectroscopy. Under a 5-h UV-Vis light irradiation, 5.01μmol/hg_cat of H₂ are yielded from photocatalytic splitting of seawater effected by (Ni-ZnO)@C nanoreactors.