气相CBr2 自由基的产生及激光诱导荧光色散谱研究

利用双层流动反应管作为束源,研究了F与CH2Br2反应生成的CBr2和Br2的气相激光诱导荧光色散谱,将得到的谱线分别指定为CBr2的(0,13,0)→(0,v2″,0)(v2″=1～6)跃迁和Br2的 3Π+u→ 1Σ+g跃迁,从光谱中首次得到气相CBr2自由基基态弯曲振动频率ν2″=215 cm-1,实验确认了CBr2自由基和Br2是F+CH2Br2过程多步反应的产物.     

Cluster-assisted generation of multi-charged ions in nanosecond laser ionization of pulsed hydrogen sulfide beam at 1064 and 532nm

The multi-charged sulfur ions of S^q= (q\le 6) have been generated when hydrogen sulfide cluster beams are irradiated by a nanosecond laser of 1064 and 532,nm with an intensity of 10¹⁰\sim 10¹²W1\cdotcm^-2. S⁶⁺ is the dominant multi-charged species at 1064nm, while S⁴⁺, S³⁺ and S²⁺ ions are the main multi-charged species at 532nm. A three-step model (i.e., multiphoton ionization triggering, inverse bremsstrahlung heating, electron collision ionizing) is proposed to explain the generation of these multi-charged ions at the laser intensity stated above. The high ionization level of the clusters and the increasing charge state of the ion products with increasing laser wavelength are supposed mainly due to the rate-limiting step, i.e., electron heating by absorption energy from the laser field via inverse bremsstrahlung, which is proportional to \lambda ², \lambda being the laser wavelength.     

CeO2-WO3催化剂表面酸性和氧化还原性能在脱硝反应中的研究

本研究利用原位合成法成功制备CeO₂-WO₃催化剂并用于脱硝反应，焙烧温度为550℃的CW-550催化剂活性最佳，200℃时CW-550脱硝活性达到90%以上。CW-550催化剂具有优越的催化剂性能可归结为较大的比表面积、较多的Ce³⁺物种、丰富的表面酸性和优越的氧化还原性能。Ce³⁺增多，有利于氧空位的形成，可促进氧化还原性能。WO₃的引入，在550℃的焙烧条件下可显著提升催化剂的Br?nsted酸量，有利于氨气的吸附与活化，提升其催化性能。CW催化剂上吸附的NH₃物种能与气态的NO反应，而吸附态的NH₃与吸附态的NO_x不能进行高效反应，因此，CW催化剂的SCR反应主要遵循Eley-Rideal反应机理。