摘要
Sn0.5Ti0.5O2催化剂对NO+CO反应活性不高,350℃时NO的转化率只有50%,但反应气中含有SO2时NO的转化率接近100%,说明SO2对Sn0.5Ti0.5O2催化剂上的NO+CO反应具有促进作用.XPS表征发现SO2+CO、SO2+NO+CO反应后催化剂表面有微量硫存在,而反应前没有检测到硫的存在.结合反应性能测定瞬变应答实验、XRD、TPD研究等,发现催化剂上的表面硫参与了NO的催化还原反应,是NO+CO反应更重要的活性中心.据此,提出了SO2+NO+CO反应的氧化还原反应机理.
SO2 shows a significant promoting effect on the activity of Sn0.5Ti0.5O2 solid solution catalyst for NO reduction with CO at 350 degreesC. The mechanism of the promotion was studied by transient techniques combined with reaction test, XRD, XPS and TPD methods. The XPS analysis proves the existence of surface sulfur species, which was formed during the CO-SO2 or CO-SO2-NO reaction. It was suggested that the surface sulfur weakened the N - O bond and promoted its split hence promoted NO reduction. Therefore, surface S is one of the more importance active site for NO reduction in the SO2-NO-CO reaction. The mechanism Of SO2 promoted NO reduction by CO was proposed.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2002年第3期193-196,共4页
Acta Physico-Chimica Sinica
基金
国家重点基础研究发展规划(G19990222)
国家自然科学基金(20077002)资助项目~~
