摘要
In this study,the thermal stability of a ferric oxide catalyst for mercury oxidation was found to be considerably promoted by doping with La_(2)O_(3).The catalysts doped with La_(2)O_(3)maintained a higher surface area when subjected to high-temperature calcination,with lower average pore size and a narrower pore size distribution.X-ray diffraction(XRD)results revealed that La_(2)O_(3)doping hinders the growth of catalyst particles and crystallization of the material at high temperatures.Both NO and SO_(2)inhibited Hg^(0)oxidation over the La_(2)O_(3)/Fe_(2)O_(3)catalyst.Fourier transform infrared(FTIR)spectra revealed that SO_(2)reacts with O_(2)over the catalysts to form several species that are inert for mercury oxidation,such as S042^(-),HS04^(-),or other related species;these inert species cover the catalyst surface and consequently decrease Hg^(0)oxidation capacity.In addition,NO or SO_(2)competed with Hg^(0)for active sites on the La_(2)O_(3)/Fe_(2)O_(3)catalyst and hindered the adsorption of mercury,thereby inhibiting subsequent Hg^(0)oxidation.Hg^(0)oxidation on the La_(2)O_(3)/Fe_(2)O_(3)catalyst mainly followed the Eley-Rideal mechanism.Moreover,the inhibition effects of NO and SO_(2)were at least partially reversible,and the catalytic activity was temporarily restored after eliminating NO or S0_(2).
基金
supported by the National Key Research and Development Program of China(No.2017YFC0210501)
the Fundamental Research Funds for the Central Universities(No.N2123031)
the National Engineering Laboratory for Flue Gas Pollutants Control Technology and Equipment(No.NEL-KF-201902).
