The Preparation Of Highly Dispersed Nanocatalysts Based On NiAl-LDHs And The Study Of Their Catalytic Performance

In the reaction process of nickel-based catalyst,the structure collapses and the active components are usually inactivated.The alumina is used as the aluminum source,and the hydrotalcite material is synthesized in situ growth method.Ruthenium nanoparticles are supported on the surface to achieve high dispersion.The highly dispersed nickel based catalysts were applied to investigate the selective hydrogenation of biomass platform 5-hydroxymethylfurfural.In addition,the preparation of ternary nickel-copper-aluminum hydrotalcite,calcined and reduced to obtain highly dispersed nickel-copper bimetallic catalyst,and then used in the biological derivatives of ethyl levulinate catalytic transfer hydrogenation perfonnance research.Layered double hydroxides(LDHs)are a kind of two-dimensional layered materials,which have attracted much attention from scientific research workers,because of their composition and proportion changeability,diverse preparation methods and excellent catalytic activities.Recently,layered double hydroxides have been investigated in the catalytic,photovoltaic,environmental pollution,flame retardant,biological sensor,medicine and other aspects by researchers.In this paper,NiAl-LDHs were synthesized by situ growth method,and the ruthenium nanoparticles were highly dispersed on their surface by chemical reduction method,which was applied to selective hydrogenation of 5-hydroxymethylfurfural.In addition,NiCuAl-LDHs were synthesized by situ growth method,the nickel-copper bimetallic catalysts were obtained by means of calcining and reducing,utilized to the study of catalytic transfer hydrogenation performance of ethyl levulinate.The relationship between catalyst structure and catalytic activity has been investigated.(?)The situ growth method was selected to synthesize NiAl-LDHs,the surface of NiAl-LDHs is rich in hydroxyls,through the chemical reduction of sodium borohydride on the surface of NiAl-LDHs loaded ruthenium nanoparticles.The ruthenium nanoparticles were uniformly dispersed on the surface of the support by XRD,SEM,HRTEM,BET and XPS characterizations.The interaction between the support and ruthenium nanoparticles was highly strong.Moreover,NiAl-LDHs have abundant pore structures and high specific surface area,which are conducive to realize the high dispersion of noble metal ruthenium.In particular,the as-synthesized Ru/NiAl catalysts can selectively hydrogenate 5-hydroxymethylfurfural to form 2,5-dimethylfuran under the condition of hydrogen as hydrogen source.The catalyst activity has been tested five times,and the catalytic activity do not decrease significantly.(?)NiCuAl-LDHs precursors were prepared by situ growth method.Highly dispersed nickel-copper bimetallic catalysts were obtained after calcination and reduction.The relationship between the structure and properties of the catalysts was analyzed by XRD,STEM,BET,TPD,FT-IR and XPS characterizations.The results show that the synergistic effect of highly dispersed nickel-copper bimetallic nanoparticles and surface acid/base sites makes the nickel-copper bimetallic nano-catalysts show excellent catalytic performance under atmospheric pressure nitrogen and isopropanol as hydrogen source(220 O N2 atmosphere)to conduct catalytic transfer hydrogenation of ethyl levulinate to produce y-valerolactone.Furthermore,the catalyst activity has been tested five times,and the catalytic activity do not decrease significantly.