Synthesis, Structure Control And Application Of Nanoscaled Zero-valent Iron Supported Ordered Mesoporous Carbon

Due to its small size and extremely high reactivity, nanoscaled zero-valent iron (NZVI) has a strong tendency to aggregate and may be self-ignite or oxidized when exposed to the air, thus limited its application. To overcome these drawbacks, we proposed to design novel supported NZVI composites using ordered mesoporous carbon as supports (Fe/OMC). In this article, ordered Fe/OMC with highly dispersed iron nanoparticles were directly synthesized through simple soft-templating routes without addition of any mineral acid by using resorcinol-formaldehyde (RF) as a carbon precursor, triblock copolymer Pluronic F127 as a template agent and hydrated iron nitrite as an iron source. The resultant materials were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen sorption and Raman spectrometry techniques. The influence of synthetic conditions on the structure of Fe/OMC was investigated in detail. By choosing 2,4,6-trinitrotoluene (TNT) as a target pollutant, we studied its absorption and degradation process using the obtained Fe/OMC materials at different reaction conditions and proposed a possible degradation mechanism. Furthermore, we investgated catalytic graphitization of OMC materials in the presence of Fe, Co, Ni and compared the electrochemical properties of Pt supported M/OMC (M=Fe, Co, Ni) materials with different graphitization degree for methanol oxidation at room temperature. The results showed that:1. In order to incorporate more iron species while maintaining the ordered structure of resultant materials, the optimized carbonization temperature, the molar ratio of resorcinol(R) to formaldehyde(F), heating rate, aging time were 800℃,1/1.5,1-5℃/min and 60h, respectively.2. The removal of TNT by Fe/OMC composites is a combined process of adsorption and degradation. The removal rate of TNT increases as the dosage and the ordered degree of Fe/OMC increased. The degradation efficiency of TNT was enhanced at low pH values. The possible degradation path of TNT was that-NO2 was firstly reduced to-NHOH and further reduced to the corresponding amino products.3. It reveals that graphitic ordered mesoporous carbon materials can be synthesized at low temperature in the presence of Fe, Co, Ni. The graphitization of the resultant materials varied as a function of the types of metal employed as catalyst (Fe>Co>Ni). It showed that Pt-Fe/OMC catalyst with higher degree of graphitization exhibited higher current density (258mA.mg-1Pt), which is 2.2 times that of commercial catalyst, and higher If/Ib(up to 1.98) in 1.0 M CH3OH and 0.5 M H2SO4 eletrolyte, indicating its strong ability to resist CO poisoning.