Surface-defect-rich mesoporous NH-MIL-125 (Ti)@BiMoO core-shell heterojunction with improved charge separation and enhanced visible-light-driven photocatalytic performance.

Mesoporous NH-MIL-125(Ti)@BiMoO core-shell heterojunctions with surface defects were fabricated through a facile solvothermal method. The mesoporous core-shell structure with a large relative surface area of 87.7 m g and narrow pore size of 8.2 nm extends the photoresponse to the range of visible light due to the narrow band gap of ∼1.89 eV. The visible-light-driven photocatalytic degradation efficiency of highly toxic dichlorophen and trichlorophenol were 93.28 and 92.19%, respectively, and the corresponding rate constants were approximately 8 and 17 times higher than the rates achieved by pristine NH-MIL-125(Ti). The photocatalytic oxygen production rate was increased to 171.3 µmol g. Recycling for several cycles indicates high stability, which is favorable for practical applications. The excellent photocatalytic performance can be ascribed to the formation of the core-shell heterojunctions and to the surface defects that favor charge separation and visible light absorption; the mesoporous structure offers an adequate number of surface active sites and mass transfer. This novel mesoporous core-shell photocatalyst will have potential applications in the environment, and this strategy offers a new insight into fabrication of other high-performance core-shell structure photocatalysts.