A mechanistic periodic DFT study on the dissociation of tetrachlorodibenzofuran (TCDF) by M-doped carbon nanotube catalysts (M = Al, Fe, Mn)

Abstract

Previous literature data showed that pristine aromatic allotropes of carbon such as graphene and carbon nanotubes (CNT) don’t show good interaction with carbon-based pollutants. On the other hand, defects or metal/non-metal doping in these inexpensive available catalysts could increase their strength for the adsorption and dissociation of different pollutants. In this work, by using periodic DFT calculations, adsorption of Tetrachlorodibenzofuran (TCDF) on pristine, co-adsorbed, defected, and M-doped carbon nanotubes (M = Al, Fe, Mn) is studied, and possible pathways for its first step dissociation is investigated. Data show that all three models of dissociations of TCDF need very high barrier energies on the surface of pristine CNT. Its minimum barrier energy is 3.31 eV which belongs to CCl bond cleavage. On the other hand, co-adsorbed, defected, and M-doped CNTs need less barrier energies. Minimum barrier energy belongs to CH bond dissociation on oxygen co-adsorbed CNT with 0.92 eV which is almost equal to the temperature of 355 K. Co-adsorbed CNT catalyst can also activate CCl chemical bond by 0.93 eV. Some catalysts such as Al-doped CNT is selective for CO bond cleavage, but some other catalysts, such as co-adsorbed CNT for CH and CCl, have similar barrier energy for two models of dissociations. With considering kinetics point of view (by barrier energies) and thermodynamics point of view (by reaction energy), data show that co-adsorbed, defected, and Al-doped CNTs are good catalysts for the first step dissociation of TCDF.