The Synthesis And Catalytic Performance Study Of Quaternary Component Amorphous Alloy Nanotubes

Due to the unique structure of long-range disorder and short-range order and the highly unsaturated surface properties,amorphous alloy,a novel kind of catalytic material,exhibites high hydrogenation catalytic activity and attracts enormous attention.However,amorphous alloys tend to reunite with each other during the preparation process leading to a low specific surface area and a further reduction of the catalytic properties.Recently,the nanotube-like amorphous alloy prepared by our group,such as Co-B,Ni-B and Fe-B nanotubes,possess improved the specific surface area and enhanced catalytic activity,which has attracted extensive interest.But binary amorphous alloy nanotubes still have some problems,for insurance the poor stability,in the catalytic reactioa By doping elements to modulate the surface electronic state and structure of the amorphous alloy is an effective way to improve the catalytic properties and structural stability.The ternary and quaternary amorphous alloy catalysts have already been reported,however,the synthesis of quaternary amorphous alloy nanotubes has not been successfully proposed yet.This thesis successfully prepared a series of quaternary amorphous alloy nanotubes with diffe rent components of Ni-Co-P-B nanotubes and Ni-Fe-P-B nanotubes via the lyotropic liquid crystal template method.By using the characterizations of X-ray powder diffraction(XRD),transmission electron microscope(TEM,HRTEM),and pore size distribution and specific surface(BET),inductively coupled plasma emission spectrum(ICP)and X-ray photoelectron spectroscopy(XPS),the structure,morphology,compositions have been analyzed.Moreover,the catalytic performance of the as-prepared nanotubes in hydrogenation was studied as well.Main work contents are summarized as follows:1.The synthesis and catalytic performance study of Ni-Co-P-B amorphous alloy nanotubes.A series of quaternary Ni-Co-P-B amorphous alloy nanotubes with uniform morphology and different compositions have been fabricated through the lyotropic liquid crystal template synthesis method with conditions optimization The preparaed amorphous alloy nanotubes catalysts have the diameter of about 60 nm,the wall thickness of about 5 nm,and the length up to a few microns.Nitrobenzene hydrogenation catalysis performance tests show that the Ni-Co-P-B nanotubes exhibit better catalytic activity than the corresponding nanoparticles.Furthermore,the Ni-Co-P-B nanotubes have enhanced performance compared to that of ternary Ni-P-B nanotubes and binary Ni-B nanotubes.The addition of an appropriate amount of Co into the Ni-P-B nanotubes can increase the catalytic activity and stability of the nanotubes.However,the excess amount of Co will weaken the catalytic hydrogenation activity.2.The synthesis and catalytic performance study of Ni-Fe-P-B amorphous alloy nanotubes.Quaternary Ni-Fe-P-B amorphous alloy nanotubes are further successfully synthesised through the method of lyotropic liquid crystal template.The catalytic performance of Ni-Fe-P-B amorphous alloy nanotubes was conducted and compared with that of Ni-Co-P-B nanotubes.Tests results show that the prepared Ni-Fe-P-B sample also have the diameter of about 60nm,the wall thickness of about 5nm,and the length up to a few microns.The phenol hydrogenation catalytic results show that both of Ni-Co-P-B nanotubes and Ni-Fe-P-B nanotubes have higher catalytic activity than that ofNi-P-B nanotubes and Ni-B nanotubes.And Ni-Co-P-B nanotubes present a better catalytic properties than that of Ni-Fe-P-B nanotubes.But the selectivity of cyclohexanol for Ni-Co-P-B nanotubes catalyst is inferior to Ni-Fe-P-B nanotubes.Research also suggests that the quaternary amorphous alloy nanotubes with appropriate composition have superior catalytic performance and stability than ternary amorphus alloy nanotubes and binary amorphous alloy nanotubes.