Gear-shaped mesoporous NH2-MIL-53(Al)/CdS P-N heterojunctions as efficient visible-light-driven photocatalysts

NH2-MIL-53(Al)/CdS p-n heterojunctions are fabricated via facile two-step hydrothermal method. The formation of p-n heterojunctions could form built-in field, which favors spatial charge separation. The resultant NH2-MIL53(Al)/CdS p-n heterojunctions with narrowed band gap extend the photoresponse, and have a high specific surface area of 417.7 m2 g-1, and a narrow pore size of 8.8 nm. Under visible light irradiation, the photocatalytic efficiency for reduction of Cr(VI) and removal of refractory pesticide trichlorophenol is up to 99.23 and 98.85 %, respectively. The photocatalytic oxygen evolution is also as high as 563.6 mu mol g-1 h-1. The excellent photocatalytic activity can be ascribed to the efficient p-n heterojunctions accelerating charge transfer and favoring spatial charge separation, and the special mesoporous structure supplying adequate surface-active sites and facilitating mass transfer. This facile strategy opens up new insights for fabricating other p-n heterojunctions photocatalysts with efficient solar energy conversion.

Automated summary

NH2-MIL-53(Al)/CdS p-n heterojunctions were fabricated using a simple two-step hydrothermal method, showing high photocatalytic efficiency for Cr(VI) reduction and trichlorophenol removal under visible light irradiation. The efficient charge transfer and spatial charge separation in the heterojunctions, along with the unique mesoporous structure, contribute to the excellent photocatalytic activity.