Study on the regulation mechanism of Al doping on the controllable photocatalytic performance of the ZnO@MgAl-LDH nanocomposite

[Display omitted] •A previously unreported binary ZnO@MgAl-LDH composite photocatalyst was developed via the hydrothermal method.•The ZnO@MgAl-LDH composite was converted from Type I to Type II by introducing Al doping into the ZnO component.•The ZnO@MgAl-LDH composite's photocatalytic performance was notably enhanced by modifying its band structure. The ZnO hollow nanospheres were initially prepared using the template method. Subsequently, MgAl-LDH nanosheets were in-situ grown on the surface of the nanospheres via the hydrothermal method, resulting in the synthesis of a type-I heterojunction-based ZnO@MgAl-LDH composite photocatalyst. However, the introduction of Al dopant into the ZnO hollow nanosphere component resulted in an elevation of the Fermi level of ZnO, which led to a change in the heterojunction type in the ZnO@MgAl-LDH composite from type-I to type-II. Consequently, the separation of photo-generated carriers in the Al-doped ZnO@MgAl-LDH composite was significantly enhanced, thereby improving its photocatalytic performance. Moreover, the mass ratio of Al-doped ZnO hollow nanospheres and MgAl-LDH was examined in greater detail to ascertain its influence on the photocatalytic performance of the composite photocatalyst. All Al-doped ZnO@MgAl-LDH composite samples exhibited enhanced photocatalytic performance in comparison to the composite sample without Al doping. Furthermore, when the mass of Al-doped ZnO hollow nanospheres was maintained at 0.100 g and the Mg2+ concentration in the precursor was 0.006530 mol/L, the resulting Al-doped ZnO@MgAl-LDH composite sample demonstrated the most optimal photocatalytic performance among all the investigated samples.