Preparation of tungsten-iron composite oxides and application in environmental catalysis for volatile organic compounds degradation

Emission of volatile organic compounds has important influence on complex air pollution and human health.In this paper,a series of tungsten-iron composite oxides with different proportions and preparation methods were synthesized and first used for catalytic combustion of chlorobenzene and toluene,as typical polluting gas sources.These WO_(3)-based solid catalytic materials were systematically characterized by modern analytical methods,and the results showed that there was strong electron interaction between W and Fe elements in the composite oxides,and the presence of a certain amount of tungsten oxide inhibited the crystallization of iron oxide,and vice versa,which were beneficial to the uniform dispersion of tungsten-iron components into each other and the improvement of redox properties.Compared with single-component oxide,the formation of tungsten-iron composite oxide affected the micro-structure,improved the specific surface area and optimized the pore structure of materials.The performance test results showed that the tungsten-iron composite oxide(FeWO_4-0.5 Fe_(2)O_(3),molar ratio of tungsten and iron was 1/2)prepared using citric acid-based sol-gel method was the optimal,and its catalytic degradation efficiency could reach 90%for chlorobenzene and 83%for toluene at 320℃,and maintain at least 60 h without obvious deactivation,with high selectivity to the formation of HCl and CO_(2).