Degradation of carbamazepine by MWCNTs-promoted generation of high-valent iron-oxo species in a mild system with O-bridged iron perfluorophthalocyanine dimers.

Metal phthalocyanine has been extensively studied as a catalyst for degradation of carbamazepine (CBZ). However, metal phthalocyanine tends to undergo their own dimerization or polymerization, thereby reducing their activity points and affecting their catalytic properties. In this study, a catalytic system consisting of O-bridged iron perfluorophthalocyanine dimers (FePcF16-O-FePcF16), multi-walled carbon nanotubes (MWCNTs) and H2O2 was proposed. The results showed MWCNTs loaded with FePcF16-O-FePcF16 can achieve excellent degradation of CBZ with smaller dosages of FePcF16-O-FePcF16 and H2O2, and milder reaction temperatures. In addition, the results of experiments revealed the reaction mechanism of non-hydroxyl radicals. The highly oxidized high-valent iron-oxo (Fe(IV)=O) species was the main reactive species in the FePcF16-O-FePcF16/MWCNTs/H2O2 system. It is noteworthy that MWCNTs can improve the dispersion of FePcF16-O-FePcF16, contributing to the production of highly oxidized Fe(IV)=O. Then, the pathway of CBZ oxidative degradation was speculated, and the study results also provide new ideas for metal phthalocyanine-loaded carbon materials to degrade emerging pollutants.

Graphene-Modified ZnO Nanostructures for Low-Temperature NO2 Sensing.

This paper develops a novel ultrasonic spray-assisted solvothermal (USS) method to synthesize wrapped ZnO/reduced graphene oxide (rGO) nanocomposites with a Schottky junction for gas-sensing applications. The as-obtained ZnO/rGO-x samples with different graphene oxide (GO) contents (x = 0-1.5 wt %) are characterized by various techniques, and their gas-sensing properties for NO2 and other VOC gases are also evaluated. The results show that the USS-derived ZnO/rGO samples exhibit high NO2-sensing property at low operating temperatures (e.g., 70-130 °C) because of their high specific surface area and porous structures when compared with the ZnO/rGO sample obtained by the traditional precipitation method. The content of rGO shows an obvious effect on their NO2-sensing properties, and the ZnO/rGO-0.5 sample has a high response of 62 operating at 130 °C, three times that of pure ZnO. The detection limit of the ZnO/rGO-0.5 sensor to NO2 is as low as 10 ppb under the present test condition. In addition, the ZnO/rGO-0.5 sensor shows a highly selective response to NO2 gas when compared with organic vapors and other inflammable or toxic gases. The theoretical and experimental analyses indicate that the enhancement in NO2-sensing performance of the ZnO/rGO sensor is attributed to the formation of wrapped ZnO/rGO Schottky junctions.