Facile synthesis and hierarchical assembly of hollow nickel oxide architectures bearing enhanced photocatalytic properties

A solvothermal method combining a calcination process was conducted to synthesize NiO hierarchical architectures with controllable morphologies and sizes. First, several hollow alpha-Ni(OH)(2) hierarchical architectures assembled by alpha-Ni(OH)(2) nanosheets had been synthesized through the solvothermal method. The nucleation-mediated mechanism overwhelmingly determined the morphology of hollow alpha-Ni(OH)(2) architectures through tuning the nucleation rate. The hollow alpha-Ni(OH)(2) spheres could be formed in the case of high nucleation rate. However, the hollow alpha-Ni(OH)(2) tubes would be obtained at low nucleation rate. Second, the hollow NiO hierarchical architecture could be obtained from the precursor without changing their morphologies by a simple calcination procedure. The as-obtained hollow NiO hierarchical architectures showed high photocatalytic property to decompose acid red I pollutant and could also be easily recycled under an external magnetic field, displaying great potential in environmental pollutant cleanup applications.