Boosting photocatalytic activity under visible-light by creation of PCN-222/g-C3N4 heterojunctions

Metalloporphyrin metal-organic frameworks are excellent photocatalyst candidates due to their strong visible-light absorbing ability, high specific surface areas, and semiconductive properties. Herein, we constructed a visible-light driven PCN-222/g-C3N4 heterojunction via a facile one-pot solvothermal method. The optimum composite with 1.0 wt% PCN-222/g-C3N4 showed the superior photocatalytic activity for degradation of RhB and Ofloxacin under visible-light irradiation, which are 3.1 and 2.97 times higher than pure g-C3N4 under same conditions. The enhanced photocatalytic activity of the PCN-222/g-C3N4 composite is attributed to the extended light response range, fast generation and efficient separation of the photo-generated carrier, and enhanced adsorption capacity of organic contaminants. Besides O2− radical and hVB+ species, OH radical is also the active species in the PCN-222/g-C3N4 photocatalytic system, which may be additional evidence for the enhanced photocatalytic activity of PCN-222/g-C3N4 with respect to pristine g-C3N4. As-prepared PCN-222/g-C3N4 photocatalyst shows excellent recyclability, which can be reused four times without significant inactivation. Therefore, PCN-222/g-C3N4 heterojunction photocatalysts have great potentiality in organic wastewater treatment.