Preparation Of Ni-based Bimetallic Nanoparticles Based On Novel Carbon Nanomaterials

Carbon nanodots(CNDs),as a new type of zero-dimensional carbon nanomaterials,are widely used in biological monitoring,medicine,catalysis and other fields due to their excellent physical and chemical properties and good biocompatibility.Ni-based nanoparticles are inexpensive and exhibit high catalytic activity in the catalytic process.The composite nano system formed by the combination of metal nanoparticles and carbon nanodots has attracted wide attention because of its high catalytic activity in catalysis.This paper proposes to use carbon nanodots as a stabilizer to prepare Ni-based bimetal/CNDs composite nanoparticles,study their various properties,and apply them to the catalytic liquefaction of lignin in supercritical methanol.The specific work includes the following parts:(1)Using trisodium citrate and urea as the carbon source and passivation agent,the carbon nanodots were prepared by the illumination method,and passed TEM(transmission electron microscope),FT-IR(Fourier transform infrared spectrometer),XPS(X-ray photoelectron energy Spectrometer),XRD(X-ray diffraction)and other characterization analysis of its microstructure and surface state.When the prepared carbon nanodots are irradiated for 30 min,spherical carbon nanodots with uniform morphology and an average particle size of 2.43 nm are obtained,and the surface contains abundant functional groups,such as OH,COOH,and C-O.Changing the irradiation time found that the longer the time,the larger the particle size,and the morphology also changed from spherical to tetrahedral.In addition,the effects of different preparation methods on the morphology,particle size and surface functional groups of carbon nanodots are discussed.(2)Ni-based bimetallic nanoparticles are prepared by hydrothermal method,and the morphology,particle size and internal structure of different metal molar ratios and PVP(polyvinylpyrrolidone)content are analyzed by SEM(scanning electron microscope)and XRD.influences.When the molar ratio of Ni:M(M=Fe,Cu,Pd)is 3:1 and the content of PVP is 1 g,good dispersion is obtained.The particle size is 31.73 nm,45.36 nm and 25.27 nm,which exist in the form of alloy.Ni-based bimetallic nanoparticles.The one-pot method,hydrothermal method,and room temperature stirring method are used to compound the carbon nanodots and bimetallic nanoparticles,and the microstructure and surface state are analyzed by TEM,XRD,FT-IR and other characterization.Different preparation methods affect the particle size and morphology of composite nanoparticles,but will not affect the existence of Ni-based bimetallic nanoparticles in the composite system;the OH,COOH and other groups on the surface of the carbon nanodots have strong strength The interaction makes the composite nanoparticles more stable.(3)The composite nanoparticles prepared by the room temperature stirring method have a stable package structure,and the carbon nanodots and the bimetallic nanoparticles are stably composited.The composite material is used to catalyze the liquefaction of lignin in supercritical methanol.Ni Pd/CNDs composite nanoparticles show good catalytic performance,and the lignin conversion rate reaches 85%.Compared with bimetallic nanoparticles without carbon nanodots,the conversion rate has been improved,indicating that the addition of carbon nanodots can be enhanced Catalytic activity of composite materials.