Catalytic reduction of SO_2 by CO over CeO_2-TiO_2 mixed oxides  

铈钛复合氧化物催化CO还原SO_2（英文）

作　　者：张丽[1] 秦毅红[1] 陈白珍[1] 彭亚光[1] 何汉兵[1] 袁依[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第11期2960-2965,共6页中国有色金属学报（英文版）

摘　　要：The structure and catalytic desulfurization characteristics of CeO2-TiO2 mixed oxides were investigated by means ofX-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and catalytic activity tests. According to the results, a CeO2-TiO2solid solution is formed when the mole ratio of cerium to titanium n（Ce）：n（Ti） is 5：5 or greater, and the most suitable n（Ce）：n（Ti） isdetermined as 7：3, over which the conversion rate of SO2 and the yield of sulfur at 500℃ reach 93% and 99%, respectively.According to the activity testing curve, Ce0.7Ti0.3O2 （n（Ce）：n（Ti）=7：3） without any pretreatment can be gradually activated by reagentgas after about 10 min, and reaches a steady activation status 60 min later. The XPS results of Ce0.7Ti0.3O2 after different time ofSO2＋CO reaction show that CeO2 is the active component that offers the redox couple Ce4＋/Ce3＋ and the labile oxygen vacancies, andTiO2 only functions as a catalyst structure stabilizer during the catalytic reaction process. After 48 h of catalytic reaction at 500℃,Ce0.7Ti0.3O2 still maintains a stable structure without being vulcanized, demonstrating its good anti-sulfur poisoning performance.利用X射线衍射(XRD),X射线光电子能谱(XPS)及活性测试对铈钛复合氧化物的结构及催化脱硫特性进行了研究。结果表明:当铈-钛摩尔比(n(Ce)/n(Ti))≥5:5时,铈钛复合氧化物形成固溶体;当n(Ce)/n(Ti)=7:3(即Ce_(0.7)Ti_(0.3)O_2)时,具有最佳的催化脱硫效果;500°C下SO_2的转化率达到93%,单质硫的产率达到99%。根据Ce_(0.7)Ti_(0.3)O_2的活性测试曲线发现:未经预处理的Ce_(0.7)Ti_(0.3)O_2约10 min后开始逐渐被反应气体活化,并在60 min后达到稳定活化状态。通过对不同反应时间下所得Ce_(0.7)Ti_(0.3)O_2进行XPS分析发现:CeO_2为活性物质,在反应过程中形成Ce^(4+)/Ce^(3+)氧化还原电对和活性氧空位,而Ti O_2仅起到稳定催化剂结构的作用。Ce_(0.7)Ti_(0.3)O_2催化SO_2+CO反应48 h后未出现硫化现象,始终保持结构的稳定,表现出较好的抗硫中毒性能。

关 键 词：CeO2-TiO2 mixed oxides solid solution catalytic reduction carbon monoxide sulfur dioxide 

分 类 号：O643.36[理学—物理化学]