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用程序升温氧化(TPO)和氢化学吸附研究了Pt/Al_2O_3和Pt-Sn/Al_2O_3催化剂的表面积炭。表明炭可沉积在金属活性中心上,也可沉积在酸性中心部位。在单铂和铂锡催化剂上都有两个代表沉积在金属中心的TPO峰。铂锡催化剂的两个峰的峰温比单铂的高,终合法制备的铂锡催化剂不仅峰温向高温位移,而且温度范围变窄。在催化剂表面积炭过程中测定的氢化学吸附表明:氢吸附量开始下降很快,并逐渐变慢直至保持不变。说明铂表面的某些部位容易积炭,另一些部位难以积炭。对于Pt/Al_2O_3,有15%的铂表面是裸露的。Sn的加入减少了表面积炭,使裸露表面增加到30%。
The surface carbon deposition of Pt / Al 2 O 3 and Pt-Sn / Al 2 O 3 catalysts was investigated by temperature programmed oxidation (TPO) and hydrogen chemisorption. Show that carbon can be deposited on the active center of the metal, can also be deposited in the acidic center. There are two TPO peaks on the single platinum and platinum tin catalysts that deposit at the metal center. The peak temperatures of the two peaks of the platinum-tin catalyst are higher than those of the platinum-alone catalyst, and the platinum-tin catalyst prepared by the final process not only shifts the peak temperature to a high temperature but also narrows the temperature range. Hydrogen chemisorption, as determined during carbon deposition on the catalyst surface, showed that the amount of hydrogen adsorbed began to drop very rapidly and gradually slowed down until it remained constant. Description of some parts of the surface of platinum easy carbon deposition, and other parts difficult to coke. For Pt / Al 2 O 3, 15% of the platinum surface is bare. The addition of Sn reduces surface carbon deposition, increasing the exposed surface to 30%.