Preparation Of Carbon-based Non-noble Metal Catalysts And Their Applications In Reduction Of Nitroaromatic Compounds And Cr(Ⅵ)

Owing to the development of industrialization,some toxic pollutants,such as p-nitrophenol(4-NP),nitrobenzene(NB),Cr(Ⅵ)and so on are rich in water body.These pollutants have a serious impact on the ecological environment,human health,but nature’s self-degradation of these pollutants is limited.Therefore,we are committed to research and treatment of such pollutants.Catalytic degradation of these pollutants in many research methods has caused attention.The research on high-efficiency,green and sustainable catalysts is a major difficulty in this field.For these pollutants,three nitrogen-doped carbon-based catalysts(NNC,CNC,Co@NC-F)composed of non-noble metals(Ni,Cu,Co)have been designed for degradation 4-NP,NB,Cr(Ⅵ),the contents are as follows:1.Synthesis,characterization and catalytic study of 4-NP liquid phase hydrogenation with NNC catalystsAs we search for a sustainable future in the catalysis field,it is necessary to learn from mother nature by using cheap,abundant and renewable biomass for the preparation of catalysts.Herein,we develop a facile and green process for the in situ construction of Ni metal nanoparticles embedded within N-doped carbon(NNC)derived from biomass daikon.In this case,biomass provides good metal ion attachment point during impregnation,in which has abundant surface containing groups,then implement the carbothermal reduction process during high temperature pyrolysis,Ni nanoparticles(Ni NPs)are generated in situ.The as-synthesized NNC catalysts were characterized by TEM,XRD,XPS,TGA.Analysis the characterization results,we found that Ni NPs were more embedded in the interior of biomass carbon evenly dispersed Among the series of NNC catalysts,the NNC-2 exhibits the best catalytic performance in the liquid-phase hydrogenation reduction of 4-Nitrophenol,which can be attributed to the structural and compositional advantages of the NNC-2 regarding large surface area,rich N-doping content and strong Ni-NC interfacial interaction.Moreover,the NNC-2 is robust and recyclable.In addition with the superior reaction performance,the cost-effectiveness and environmental benignity also endow the NNC-2 a potential industrial application prospect in the NHR and beyond.2.Synthesis,characterization and catalytic study of NB liquid phase hydrogenation with CNC catalystsThe emphasis of this chapter is to construct efficient,stable and low-cost catalysts using biomass as precursors and simple synthesis process.Without adding other reagents,cushaw and Cu salt were used to prepare uniform Cu nanoparticles(Cu NPs),which were embedded in nitrogen-doped carbon.Among these catalysts,CNC-800,which was prepared by high temperature pyrolysis at 800℃,showed superior reactivity and good stability when reducing NB in liquid phase.Both experimental studies and DFT calculations showed that there is a strong interaction between Cu NPs and adjacent carbon layers,interfacial electron transfer and Cu-Nx species,which promote the adsorption and activation of NB molecules.This chapter provides new ideas for the research of interfacial catalysis-driven NB reduction reactions,and provides a new direction for the application of high-value,abundant and cheap biomass in high-efficiency catalysis.3.Synthesis,characterization and catalytic study of Cr(VI)with Co@NC-F catalystsUsing urea,citric acid,sodium chloride and cobalt nitrate hexahydrate as raw materials,Co@NC-F series catalysts were prepared for catalytic reduction of Cr(VI).The effect of reagent component on performance was investigated,and the results showed that the performance of the urea-containing component was better than that of the non-urea component;the pyrolysis temperature found that the Co@NC-F 700 catalyst prepared by pyrolysis at 700℃ had the best effect among the series of catalysts.Analyze samples through a variety of characterization methods,such as SEM,TEM,XRD,XPS,etc.It was found that urea component,cobalt nanoparticles and nitrogen-doped carbon coordinated with each other to promote charge transfer and improve the catalytic performance.Co@NC-F 700 had the best catalytic performance.Owing to its extended 3D spatial configuration and large specific surface area,providing abundant active sites and the largest content of Co-Nx species,which is conducive to reduction reactions.