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 are...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).展开更多
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).
文摘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).
