Controlled Preparation Of High Load Non-Noble Metal Single-Atom Catalysts And Their Catalytic Performance

In recent years,environmental pollution and energy shortage are getting worse,so it is urgent to explore a catalyst with low cost,outstanding performance and environmental friendliness.As a new concept in the field of heterogeneous catalysis,single-atom catalysis is widely concerned because its atomic utilization rate can reach as high as 100%.However,due to high surface energy,the metal loading capacity in the known noble metal single-atom catalysts is generally low,which seriously affects the application scope of the related catalytic industry.Therefore,it is of great significance to develop a high activity,high selectivity and high stability non-noble metal single-atom catalyst to promote the development of human being life and production.This thesis mainly conserns to synthesis of a series of high loads of non-noble metal catalyst by physical grinding and the high-temperature pyrolysis method,a variety of characterization methods are used to characterize the structure of the as-synthesized material.Several typical heterogeneous catalysis reactions have been performed in order to evaluate the performance of the catalyst.The work in the thesis includes the following two aspects:(1)The dicyandiamine was calcined in nitrogen and oxygen atmosphere in turn to obtain ECN,and then it was ground with iron phthalocyanine at different mass ratios and calcined in a tube furnace at 600 o C in the atmosphere of nitrogen.A new photosensitized catalyst of atomically-dispersed Fe atom anchored to nitrogen-doped carbon skeleton was prepared by controlled pyrolysis.Physical adsorption apparatus,transmission electron microscopy,X-ray powder diffraction and other characterization techniques have been used to characerize the synthesized catalyst,which showed its high specific surface area,abundant and highly exposed Fe active sites.The degradation efficiency of rhodamine B bymonodispersed Fe catalyst reached 96.8% within 30 min and the activity changed little after 8 cycles.The above results indicate that this simple and efficiently prepared monodisperse Fe catalyst has important application value in fast degradation of industrial organic dyes.(2)Cobalt phthalocyanine and dicyandiamide were physically ground and calcined in a tube furnace at 800 o C in nitrogen atmosphere to prepare nitrogen-doped layered carbon loaded single-atom cobalt catalyst.The effects of different ratio of reacants and pyrolysis temperature on the oxidation and esterification of benzyl alcohol were studied.The results showed that the Co SAs@NC-800-50 catalyst had high specific surface area,pore volume and large pore diameter,and thus it had good performance on the oxidation and esterification of benzyl alcohol.Notably,the catalytic activity and selectivity for derivatives of benzyl alcohol can reach as high as 99%,indicatingh its great significance for selective oxidation of alcohol.Thus,this work provides a green and efficient synthesis method for organic synthesis of aldehydes,acids,acetaldehyde and esters etc.