• 关键词：氮氧化物  氯苯  CeWO_x催化剂  协同脱除  竞争性吸附  多污染物耦合

• 基金项目：国家自然科学优秀青年基金（No.21922607）；浙江省自然科学杰出青年基金（No.LR19E080004）

• 于宇雷
• 浙江大学， 环境与资源学院，杭州 310058

• 翁小乐
• 浙江大学， 环境与资源学院，杭州 310058;浙江省工业锅炉炉窑烟气污染控制工程技术研究中心，杭州 310058

• 吴忠标
• 浙江大学， 环境与资源学院，杭州 310058;浙江省工业锅炉炉窑烟气污染控制工程技术研究中心，杭州 310058

• 摘要：多污染物协同控制是大气污染控制技术的发展方向.本文以氮氧化物（NO_x）及氯苯（CB）为典型多污染物组分，考察了不同Ce/W比例CeWO_x催化剂协同脱除NO_x及CB的催化性能及反应特征.其中，Ce₈W₁O_x催化剂表现出最佳的催化活性，在温度为350 ℃时，NO_x、CB转化率均达到100%.NO_x选择性催化还原（SCR）、CB催化氧化（CBCO）和协同脱除反应（SCR+CBCO）的对比实验发现，协同反应的NO_x和CB转化均受到不同程度的抑制，尤以SCR对CBCO的抑制作用更为明显.TPSR及DRIFT表征证明NH₃和CB之间的竞争性吸附是SCR和CBCO协同反应活性下降的主要原因.CeWO_x催化剂上CB解离生成的氯经氧空位活化形成Cl·，易导致亲电加氯反应从而促进多氯苯生成.SCR为CBCO提供了额外氢，源于NH₃吸附于Lewis酸位点并被氧空位上活性氧物种攻击脱氢生成酰胺物种（NH₂^-/NH^-）的反应过程，该氢源促使Cl·/Cl^-以HCl形式从催化剂表面脱离.苯甲腈等含氮副产物的存在表明SCR及CBCO协同反应的中间产物发生了多污染物耦合.

• Abstract：The synergistic elimination of multi-pollutant represent the developing direction of air pollution control technology. In this paper， the synergistic elimination of nitrogen oxides （NO_x） and chlorobenzene （CB）， as typical composite pollutants， on CeWO_x catalysts with different Ce/W ratios was studied. Ce₈W₁O_x exhibited the best catalytic activity， which achieved both NO_x and CB conversion rate of 100% at 350 ℃. The comparative experiments of selective catalytic reduction （SCR） of NO_x， CB catalytic oxidation （CBCO） and synergistic reaction （SCR+CBCO） indicated that NO_x and CB conversation were inhibited in different degrees， where CBCO reaction was inhibited more obviously by SCR. The results of TPSR and DRIFT characterizations showed that competitive adsorption between NH₃ and CB contributed the most to their deactivations. Chlorine dissociated from CB on Ce₈W₁O_x catalyst formed Cl· at oxygen vacancy， which facilitated the polychlorobenzene formation via an electrophilic chlorination reaction. SCR provided additional hydrogen for CBCO due to the reaction process of NH₃ adsorbed to Lewis-acid site and dehydrogenated to form amide species （NH₂^-/NH^-） as attacked by reactive oxygen species on oxygen vacancies， which promoted the separation of Cl·/Cl^- in the form of HCl from the catalyst surface. The detection of nitrogen-containing byproducts such as benzonitrile showed that multi-pollutant coupling occurred between the intermediate products of SCR and CBCO reactions.

• Key words：NO_x  chlorobenzene  CeWO_x catalysts  synergistic elimination  competitive adsorption  multi-pollutant coupling

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