Preparation And Microstructure Of Tourmaline Supported Ni-NiAl₂O₄ Composites

Nickel-based catalysts have the advantages of high catalytic activity and low price,and have attracted attention in many fields.However,at present,nickel-based catalysts still have the disadvantages of single carrier and low dispersion of active components,which is not conducive to their large-scale industry application.Therefore,it is necessary to design a nickel-based catalyst with good dispersion and excellent catalytic performance.Tourmaline is a relatively abundant functional mineral,and there are abundant nucleation sites on the surface of the tourmaline,which is helpful for improving the dispersion of catalysts.In addition,tourmaline also has many unique properties such as spontaneous polarization,far infrared radiation and so on.Using tourmaline as the carrier for nickel-based catalyst is expected to have a synergistic effect with the active components,thus improving the dispersion of active components.In this thesis,tourmaline supported Ni-NiAl₂O₄ composites with tourmaline as the carrier and nickel aluminate as intermediate layer were studied.The composites were prepared by microwave hydrothermal-reduction method and microwave-assisted coprecipitation-reduction method,respectively.The optimal preparation processes of these two methods were determined by XRD,FTIR,SEM and other comprehensive analysis.Finally,the catalytic dry methane reforming（DRM）performance test of the tourmaline supported Ni-NiAl₂O₄ composites were carried out,and the following conclusions were drawn:（1）The optimal parameters of tourmaline supported Ni-NiAl₂O₄ composites prepared via microwave hydrothermal-reduction method were:10 vol.%of triethanolamine,220℃ of microwave hydrothermal temperature,7.4 wt.%of tourmaline additional content,800℃ of the calcined temperature,and 650℃ of the reduced temperature.The prepared Ni-NiAl₂O₄/tourmaline composites have good microstructure.（2）The optimal parameters of tourmaline supported Ni-NiAl₂O₄ composites prepared via microwave-assisted coprecipitation-reduction method were:9 of the pH value for precursor solution,0.25 wt.%of sodium dodecylbenzene sulfonate,9.1 wt.%of tourmaline additional content,750℃ of calcined temperature,and 650℃ of the reduced temperature.The prepared Ni-NiAl₂O₄/tourmaline composites have uniform morphology and good dispersion.（3）Both of the Ni-NiAl₂O₄/tourmaline composites prepared by the above two methods have good dispersion,and the composite prepared via microwave assisted coprecipitation method need a lower calcination temperature.NiAl₂O₄ also effectively limits the size of Ni particles in the reduction process.In addition,compared with Ni-NiAl₂O₄,the Ni-NiAl₂O₄/tourmaline composites effectively improved the activity of the catalyst at low temperature（500～600℃）in the DRM reaction,and the composites prepared via microwave hydrothermal-reduction method have higher H₂/CO ratio.