自然光老化对PVC-O管材外观及力学性能的影响

考察了自然光老化对PVC-O管材外观颜色、尺寸、表面微观情况和力学性能的影响.结果表明:短期内自然光老化对PVC-O管材力学性能的影响不大,但对外观颜色及尺寸的影响明显,管材表面出现粉化现象,不建议在户外长期使用PVC-O管材.     

费托合成催化剂Co-CeO2/SiO2的研究

A series of Co (10.7 wt. %)-CeO2/SiO2 catalysts with various cerium contents was prepared and evaluated. The optimized ceria-promoted catalyst exhibits good activity, high selectivity towards long chain hydrocarbons, and excellent stability. The promotion mechanism of ceria was investigated using X-ray diffraction (XRD), temperature programmed reduction (TPR), H2 temperature programmed surface reaction (H2-TPSR) and transient response technique. It is suggested that the improved catalytic performance of the catalyst modified by ceria be attributed to (1) the improvement in the dispersion of metallic cobalt and the amount of active sites for Fischer-Tropsch Synthesis (FTS), leading to an increased concentration of surface active carbon species and high selectivity towards long chain hydrocarbons; (2) the inhibition of disproportionation of CO and the removal of inactive surface carbon species.     

用瞬变响应技术研究CeO2在Co-CeO2/SiO2 费托合成催化剂中的作用

使用包括脉冲和CO-TPD在内的瞬变响应技术研究了CeO2在Co-CeO2/SiO2费托合成催化剂中的作用.结果表明,氧化铈可提高表面反应中间物种金属甲酸盐的热稳定性,使其容易加氢生成更多的有用产物,较难生成CO2,从而抑制催化剂的表面积碳,提高了催化剂的活性和稳定性.     

铋复合盐在乙炔氢氯化反应中的催化作用

采用浸渍法制备了以SiO2为载体、铋、铜等金属的氯化物和磷酸盐为活性组分的无汞催化剂,并测试了该催化剂在乙炔氢氯化反应中的活性. 结果表明,催化剂中加入PO43-可以显著提高催化活性,其中Bi和Cu的复合磷酸盐比其他催化剂有更好的活性,在200℃的反应温度下,其初始反应活性为工业氯化汞催化剂的1/3,且催化剂有一定的可再生性. 催化剂在反应和再生过程中存在失活,主要是由Bi的流失造成的,积炭则是另一个失活原因.