碳夹铂三明治包覆Fe_(3)O_(4)纳米颗粒材料催化硝基苯加氢制对氨基苯酚

Carbon and Platinum Sandwich Coated Fe_(3)O_(4) Nanoparticles Catalyzed Hydrogenation of Nitrobenzene to p-Aminophenol

采用二次包覆法制备了新型碳夹铂三明治包覆Fe_(3)O_(4)纳米颗粒材料(Fe_(3)O_(4)@C/Pt/C),运用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线光电子能谱(XPS)等对其进行了系统表征,并考察了不同催化剂催化硝基苯加氢制对氨基苯酚的性能。研究表明:碳化温度影响Fe_(3)O_(4)@C/Pt/C的形貌、孔结构及催化性能,在800℃下制备的Fe_(3)O_(4)@C/Pt/C-800催化剂具有较好的催化硝基苯加氢制对氨基酚性能,硝基苯转化率为94.8%,对氨基苯酚选择性为80.4%。碳夹铂的三明治碳层对Fe_(3)O_(4)核起到保护作用,有效提高了Fe_(3)O_(4)@C/Pt/C的耐酸性能,在酸性介质中循环反应4次后,硝基苯转化率仍达到94.5%,对氨基苯酚选择性为70.2%。催化剂中的Fe_(3)O_(4)核与外围三明治碳层中的Pt粒子具有协同作用,有效抑制硝基苯在金属活性位上的过度加氢,赋予催化剂更高的对氨基苯酚选择性。

A novel material of Fe_(3)O_(4)nanoparticles coated by sandwich-like structure of carbon and platinum(Fe_(3)O_(4)@C/Pt/C)was prepared by double coating method.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscope(TEM),and X-ray photoelectron spectroscopy(XPS).The hydrogenation performance of nitrobenzene to p-aminophenol over different catalysts was investigated.The results showed that the carbonization temperature affected the morphology,pore structure,and catalytic performance of the Fe_(3)O_(4)@C/Pt/C.The Fe_(3)O_(4)@C/Pt/C-800 prepared at 800℃exhibited better catalytic performance of nitrobenzene to p-aminophenol,the conversion of nitrobenzene was 94.8%,and p-aminophenol selectivity was 80.4%.The sandwich layer of carbon and platinum could protect the Fe_(3)O_(4)nucleus,which effectively improved the acid resistance of the catalysts.After four cycles of reaction in acidic media,the conversion of nitrobenzene is 94.5%,and the selectivity of p-aminophenol is 70.2%.The synergy of Fe_(3)O_(4)core and the platinum nanoparticles of the sandwich-like carbon layer effectively inhibited the excessive hydrogenation of nitrobenzene at the metal active sites,leading a higher selectivity to p-aminophenol.