论文部分内容阅读
以H_2S为毒物,H_2-O_2反应为模型反应,用浸渍法制备了一系列Pd/Al_2O_3催化剂,用交替-脉冲微反应色谱技术对催化剂活性、耐硫性进行评价,用XPS、红外分析技术对不同反应阶段的催化剂进行了表征。结果表明:在一定条件下,虽然催化剂上有S_2~(2-)、S~(2-)和SO_4~(2-)物种存在,其活性也基本相同,但耐硫性差别较大。当催化剂上有S_2~(2-)存在时,其耐硫性较差,含有S~(2-)的催化剂次之,含有SO_4~(2-)的催化剂的耐毒性较好。SO_4~(2-)对催化剂的主要影响是降低了催化剂的活性,而对抗硫性影响不大。由此可以认为,H_2-O_2反应中负载型钯催化剂硫中毒时,以S_2~(2-)毒性最大,其次是S~(2-),在一定范围内SO_4~(2-)的毒性较小。
A series of Pd / Al 2 O 3 catalysts were prepared by impregnation method using H 2 S as a poison and H 2 O 2 as a model reaction. The catalytic activity and sulfur resistance of the catalysts were evaluated by using alternating-pulse microreaction chromatography. XPS and IR analysis Catalysts at different reaction stages were characterized. The results showed that under certain conditions, although S_2 ~ (2 -), S ~ (2-) and SO_4 ~ (2-) species existed on the catalyst and their activities were basically the same, the sulfur tolerance was quite different. When S_2 ~ (2-) was present, its sulfur resistance was poor, followed by S ~ (2-), followed by SO_4 ~ (2-). The main effect of SO_4 ~ (2-) on the catalyst is to reduce the activity of the catalyst, but has little effect on the sulfur resistance. From this, it can be concluded that the sulfur toxicity of the supported palladium catalyst in H 2 O 2 reaction was highest with S 2 2- toxicity followed by S 2 2-, and the toxicity of SO 4 2- in the range of H 2- small.