助剂Ga对Pt基催化剂脱氢性能的影响

Effect of Additive Ga on Dehydrogenation Performance of Pt-Based Catalyst

通过添加助剂调控Pt基催化剂的活性相,可以达到提高催化剂选择性和稳定性的目的。以Ga为助剂,通过改变n(Ga)/n(Pt)调控Pt基催化剂的活性相,并采用BET、FT-IR、TG、H_(2)-TPR等手段对其进行了表征;在反应温度为580℃、体积空速为2000 h^(-1)、氢烃比(氢气与丙烷的体积比)为1的条件下,研究了Pt基催化剂脱氢性能。结果表明,Pt7Ga/Al_(2)O_(3)催化剂中的Pt粒径最小,分散性最好;Pt7Ga/Al_(2)O_(3)催化剂脱氢性能最好,反应3 h的丙烯选择性为90.98%,比PtSn/Al_(2)O_(3)催化剂高3.01%;Ga的调控增强了Pt与载体Al_(2)O_(3)间的作用力,降低了催化剂的酸性和催化剂的石墨化程度。

The selectivity and stability of Pt-based catalysts can be improved by adjusting the active phase by adding additives.The active phase of Pt-based catalyst was regulated by changing n(Ga)/n(Pt)with Ga as an additive and characterized by BET,FT-IR,TG,H_(2)-TPR,etc.The n(Ga)/n(Pt)of the active phase was optimized under the reaction temperature of 580℃,volume space velocity of 2000 h^(-1)and hydrogen-hydrocarbon ratio(volume ratio of hydrogen to propane)of 1.The results show that the Pt in the Pt7Ga/Al_(2)O_(3)catalyst has the smallest particle size and the best dispersion.The Pt7Ga/Al_(2)O_(3)catalyst has the best dehydrogenation performance,and the propylene selectivity of the reaction for 3 h was 90.98%,which was 3.01%higher than that with the PtSn/Al_(2)O_(3)catalyst.The regulation of Ga can enhance the interaction force between Pt and Al_(2)O_(3)support,lower the acidity of catalyst and the degree of graphitization of catalyst carbon deposition.