Pd-Fe/AC双金属催化剂在冶金、化工及环境等领域应用广泛,但受制备方法的限制,传统的液相还原法制备的Pd-Fe双金属催化剂活性物易团聚且晶粒粒度难以控制.以活性炭为载体,用超声浸渍-超声液相还原法制备出Pd-Fe/AC双金属催化剂,并通过FTIR(红外光谱)、XRD(X射线衍射)、HRTEM(高分辨透射电镜)、XPS(X射线光电子能谱)对催化剂进行表征,伏安特性曲线和计时电流曲线评价了催化剂的性能.结果表明活性炭载体的最佳改性工艺为:质量分数15%的HNO3、反应温度50 ℃、反应时间1 h;催化剂的活性成分粒径6.27 nm,晶格间距0.222 nm;经电化学测试,耦合法制备出的催化剂比液相还原法的催化活性高了 14%,并保持了更高的电化学稳定性.结论表明:相较于液相还原法,耦合法能够制备出更加高效稳定的Pd-Fe/AC双金属催化剂.
Pd-Fe/AC bimetallic catalyst is widely used in metallurgy,chemical engineering and environmental industry.However,due to the limitation of preparation methods,the active substances of Pd-Fe bimetallic catalyst prepared by traditional liquid reduction method is easy to agglomerate and the particle size is difficult to control.Pd-Fe/AC bimetallic catalyst was prepared by ultrasonic impregnation and followed by ultrasonic liquid reduction method with activated carbon as carrier.The catalyst was characterized by FTIR,XRD,HRTEM and XPS,then the performance of the catalyst was evaluated by volt-ampere characteristic curve and chronoamperometry.The results show that the optimum modification process of activated carbon carrier is as follow:mass fraction 15%HNO3,reaction temperature 50 ℃,reaction time 1 h.The particle size of the active component in the catalyst is 6.27 nm,and the lattice spacing is 0.222 nm.Electrochemical tests show that the catalyst prepared by the coupling method has a catalytic activity of 14%higher than that of the liquid reduction method,and maintains higher electrochemical stability.The results show that the coupling method can prepare a more efficient and stable Pd-Fe/AC bimetallic catalyst than the ultrasonic liquid reduction method.