Constructing ZIF-8 derived C-ZnS/ZnMoO4@MoS2 and C-ZnS/MoS2 nanocomposites using a simple one-pot strategy to enhance photocatalytic degradation activity.

Efficient C-ZnS/ZnMoO4@MoS2 and C-ZnS/MoS2 nanocomposite photocatalysts, using ZIF-8 derived C-ZnO as a precursor were successfully synthesized using a simple one-pot procedure. This is the first application that involves transforming ZIF-8 into C-ZnMoO4 for photocatalysis. The C-ZnS/ZnMoO4@MoS2 and C-ZnS/MoS2 heterostructures were characterized by X-ray diffraction, UV-vis, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, photocurrent measurements, scanning electron microscopy and transmission electron microscopy. The ZM2 sample of C-ZnS/ZnMoO4@MoS2 exhibited enhanced photocatalytic activity of about 2.9 times as high as that of ZIF-8 derived C-ZnO in the reduction of tetracycline hydrochloride, and also showed obvious photocatalytic activity 1.81 and 3.33 times as high as that of a ZM3 sample of C-ZnS/MoS2 and ZIF-8 derived C-ZnO in the degradation of RhB, respectively. The improved photodegradation activity is a result of the heterogenous structure and the tighter contact between C-ZnS and C-ZnMoO4 compared with the physical contact of general heterogenous photocatalysts. The C-ZnS/ZnMoO4@MoS2 heterostructure photocatalyst is expected to be a new type of nanomaterial for the degradation of pollutants from wastewater.

C-doped ZnO decorated with Au nanoparticles constructed from the metal-organic framework ZIF-8 for photodegradation of organic dyes.

Recently, engineering metal-organic frameworks (MOFs) into metal oxides by solid state thermal decomposition has attracted wide attention for photocatalytic applications. Here, a series of C-doped ZnO materials decorated with Au nanoparticles (Au/C-ZnO) were constructed via controlled pyrolysis of ZIF-8 adsorbing different amounts of HAuCl4·4H2O. In this pyrolysis process, ZIF-8 was transformed into C-doped ZnO according to the EDX and XPS analysis. Meanwhile, HAuCl4·4H2O was transformed into Au nanoparticles that were uniformly dispersed on the surface of C-ZnO as seen in TEM images. The photocatalytic activity of as-prepared catalysts was evaluated by the degradation of methyl orange under UV-vis light irradiation. It was found that the photocatalytic activity of Au/C-ZnO was better than C-ZnO and pure ZnO. Furthermore, Au/C-ZnO exhibited high photocatalytic stability. After three consecutive cycles, there was no noticeable deactivation in the reaction. This unusual photocatalytic activity was attributed to the synergistic effect of C-doping and Au NPs.