挥发性有机化合物(VOCs)作为细颗粒物（PM2.5）、臭氧（O3）复合型污染物的重要前驱体，其治理工作已被列为国家“十三五”环保治理的重要任务之一；“十四五”进一步指出，要加强城市大气质量达标管理，推进PM2.5和O3协同控制，加快挥发性有机物排放综合整治。在各种VOCs处理技术中，催化燃烧处理VOCs效率高、无二次污染，是VOCs处理的最有效方法之一。但在实际应用过程中，煤化工（焦化）等工业源排放的有机废气中均存在含硫组分，会与催化剂作用导致催化剂硫中毒。因此，对催化剂进行调控设计，提高催化剂的耐硫性对VOCs治理具有重要意义。通过分析VOCs的催化燃烧机理，指出活性氧在催化燃烧VOCs过程中的重要作用；分析了催化剂的硫中毒机理，指出催化剂硫中毒的原因，根据催化燃烧和硫中毒机理归纳总结了提高催化剂耐硫性的途径；同时，给出了耐硫性催化剂的表征技术。最后，根据国内外研究现状和技术水平，指出目前耐硫催化剂合成中存在的困难和未来的研究重点。VOCs的催化燃烧有3种反应机理，活性氧类型与反应机理相关，而活性氧类型和浓度与催化剂的耐硫性密切相关，因此，确定催化反应机理，明析活性氧物种类型，提高催化剂的氧还原能力对提高催化剂的耐硫性至关重要。根据催化剂的硫中毒机理，硫化物与VOCs分子竞争吸附占据吸附活性位点，导致活性位点减少，催化剂失活；硫化物与催化剂组分发生化学反应生成硫酸盐，堵塞催化剂孔道，覆盖催化剂活性位，导致催化剂硫中毒。通过引入助剂可以调节催化剂的酸碱性，催化剂的弱酸性可以减弱对硫化物的吸附；通过引入助剂和添加可硫酸化载体可以减弱活性组分与硫化物的作用，减弱活性组分的硫酸化；水和硫化物在催化燃烧体系中共存时，可阻碍硫酸根在催化剂表面的沉积，含有大量表面羟基的湿式硫酸盐催化剂具有更高的表面酸性，从而促进催化活性。通过提高催化剂的氧化还原性能、抑制对硫化物的吸附、减弱活性组分与硫化物的作用及调控气体组成4种手段可改善催化剂的耐硫性。

Volatile organic compounds (VOCs) are important precursor of fine particulate matter(PM2.5) and O3 compound pollutants. VOCs pollution control has been listed as one of the important tasks in Chinese "13th Five Year Plan" environmental protection management. The “14th Five Year Plan” further pointed out that it is necessary to strengthen the management of urban air quality,promote the collaborative control of PM2.5 and O3,and accelerate the comprehensive treatment of volatile organic compounds emissions. Among various VOCs treatment technologies,catalytic combustion is the most effective method for VOCs treatment because of its wide range in the treatment concentration and no secondary pollution. However,there are usually a certain amount of sulfur compounds in the organic waste gas from coal chemical industry,coking plants,petroleum refineries and other industrial sources in the practical application process,which can interact with the catalyst to cause sulfur poisoning of the catalyst. Therefore,it is of great significance to control and design the catalyst and improve the sulfur tolerance of the catalyst for the treatment of VOCs. By analyzing the mechanism about the catalytic combustion of VOCs the important role of active oxygen in the process of catalytic combustion of VOCs was pointed out. The mechanism about sulfur poisoning of the catalyst was analyzed. The main causes about sulfur poisoning of the catalyst were given. According to the combustion mechanism and sulfur poisoning mechanism of the catalyst,four ways to improve the sulfur tolerance of the catalyst were summarized. Meanwhile,the characterization techniques of sulfur tolerance catalyst were given. On the basis of the global research status and technical level,the difficulties in the synthesis of sulfur tolerant catalysts and the future research focus were pointed out. There are three reaction mechanisms for the catalytic combustion of VOCs. The type of active oxygen is related to the reaction mechanism,and the type and concentration of active oxygen are closely related to the sulfur resistance of the catalyst. Therefore,it is of great significance to determine the catalytic reaction mechanism,analyze the type of active oxygen species and improve the oxygen reduction ability of the catalyst for the sulfur resistance of the catalyst. According to the sulfur poisoning mechanism of the catalyst,sulfides competed with VOCs to occupy the adsorption active sites,the active sites are reduced,and the catalyst is inactivated; sulfur compounds react with catalyst components to form sulfate,which blocks catalyst channels and covers catalyst active sites,resulting in sulfur poisoning of the catalyst. By introducing promoters,the acid and alkalinity of the catalyst can be adjusted,and the weak acidity of the catalyst can weaken the adsorption of sulfide. By introducing promoters and adding sulfating supports,the interaction between active components and sulfide can be weakened,and the acidification of active components can be weakened. The coexistence of water and sulfide in the catalytic combustion system can prevent the deposition of sulfate radical on the catalyst surface. The wet sulfate catalyst containing a large number of surface hydroxyl groups has higher surface acidity,thus promoting catalytic activity. The sulfur resistance of the catalyst can be improved by improving the oxidation-reduction performance of catalyst,inhibiting the adsorption of sulfide,weakening the interaction between sulfide and catalysts and controlling the composition of raw gas.

0 引言

1 催化燃烧VOCs机理

   1.1 Mars-van-Krevelen机理

   1.2 Langmuir-Hinshelwood机理

   1.3 Eleye-Rideal机理

2 催化剂硫中毒机理

   2.1 硫化物种类的影响

   2.2 载体理化性质的影响

   2.3 反应温度的影响

3 催化剂耐硫性改善方法

   3.1 氧化还原性的增强

   3.2 硫化物吸附性能抑制

   3.3 活性组分的保护

   3.4 水蒸气调控

4 VOCs燃烧催化剂的表征手段

5 结语及展望