摘要
采用双股并流共沉淀法制备了SnCuO系列催化剂 ,测定了它们对甲烷燃烧反应的催化活性及抗硫中毒性能 ,并采用XRD ,BET ,XPS ,DTA TG和FT IR等技术对催化剂进行了表征 .比表面积和活性测试结果表明 ,SnCuO系列样品的比表面积均大于纯氧化物 ,其低温催化活性大大高于纯氧化物 .在Sn Cu原子数比接近 1时 ,其比表面积最大 (超过 10 0m2 g) .具有最大比表面积的样品SnCu4和SnCu5的活性最高 .进一步测定了SnCu4样品的抗硫中毒性能 .结果发现 ,在 5 0 0℃下 ,反应刚开始时甲烷的转化率为 98% ,随着SO2 的不断通入 ,催化剂的活性逐渐降低 ,到 12h后基本稳定 ,此时甲烷转化率仅为5 0 % .采用FT IR和热重分析方法对SnCu4硫中毒的机理进行了研究 ,发现其中毒原因在于SnCuO系列催化剂中的CuO与SO2 反应几乎完全转化为CuSO4。
Catalytic combustion of methane is an effective way to utilize it as an energy source, or to prevent it from polluting the atmosphere. It was found that the binary metal oxides based on SnO_2 displayed quite high activity for the deep oxidation of methane. The binary SnCuO catalysts were prepared by a modified co-precipitation method and characterized by XRD, BET, XPS, DTA-TG and FT-IR. The catalytic activity of the catalysts for methane combustion as well as their resistance to sulfur poisoning were investigated. The results showed that the surface areas of all SnCuO catalysts are bigger than pure SnO_2 or CuO, especially for the samples with n(Sn)/ n(Cu)≈1, their specific surface areas are bigger than 100 m 2/g. The catalytic activity of the catalysts at low temperature is higher than pure SnO_2 or CuO. SnCu4 and SnCu5 with the biggest specific surface area show the highest catalytic activity. For sample SnCu4, the resistance to sulfur poisoning, which is an important factor for the catalysts, was also investigated. SO_2 was added into the source gas ( φ(SO_2)=0.02%) and the catalytic activity was measured at 500 ℃. The CH_4 conversion was 98% at the beginning, but decreased gradually and kept stable after 12 h with CH_4 conversion of 50%. The mechanism of sulfur poisoning was further studied by FT-IR and DTA-TG methods and it was found that the deactivation of the catalysts under SO_2 is due to transformation of CuO into CuSO_4.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2003年第3期229-232,共4页
基金
国家重点基础研究发展规划项目 (G2 0 0 0 0 775 0 3)
国家自然科学基金资助项目 ( 2 980 30 0 1)
