两种二氧化硅负载钯催化体系的制备及其在4-硝基苯酚催化降解中的应用

Preparation of two palladium-catalyst systems supported by silica and their application in the reduction of 4-nitrophenol

采用一步合成法和分步合成法制备了胺基改性二氧化硅,并通过浸渍法制备得到两种二氧化硅负载钯的催化体系.通过紫外-可见光谱(UV-Vis)、红外光谱(FTIR)、扫描电镜(SEM)、X射线衍射(XRD)和马尔文激光粒度仪等分析方法对催化体系的微观结构和催化性能进行了研究,并对比了这两种催化体系的催化活性和循环使用性能.实验结果表明,由一步法和分步法制得的催化体系的直径分别为3.15μm和0.35μm左右,均能很好地负载金属钯,制备出两种含钯的高效催化剂.它们对模拟污染物4-硝基苯酚都有较高的催化活性,但在循环性能测试中,采用一步法得到的催化体系比分步法制备的体系表现出更好的催化活性.

Amine modified silica was prepared by one-step method and step-by-step method, and two kinds of palladium catalysts supported by silica were prepared by impregnation method. The micro structure and catalytic properties were studied by UV-visible absorption spectroscopy （UV-VIS） , infrared spectra （ FTIR ） , scanning electron microscopy （ SEM ） , X-ray diffraction （XRD） and Malveru laser particle size analyzer. The experimental results showed that the diameter of the catalyst system were 3. 15 Ixm and 0. 35 μm,respeetively,both had good load capacity for palladium. Therefore,both of them displayed good catalytic activity for the reduction of 4-nitrophenol. In addition, the catalytic system prepared by one-step method showed better catalytic activity than that prepared by the step-by-step method in the cyclic performance test.