Preparation And Application Of Co-N-C In The Oxidation Of C-H Bond With Nitrogen Containing Biomass As Precursor

In the field of chemical industry,catalysts are playing a more and more important role.More than 90%of the chemical reaction is carried out with catalysts,which is involved in extensive areas of petroleum processing,chemical production,organic synthesis,pharmaceutical etc.Therefore,the development of catalysts with high activity,high selectivity and high stability has become the focus of the relevant enterprises and production units.In recent years,due to its high catalytic activity,good stability and facile preparation,M-N-C materials have attracted much attention in the fields of electrocatalysis,aerobic oxidation,photocatalysis,hydrogenation and so on.However,the traditional methods for the preparation of M-N-C by a direct pyrolysis of macrocyclic compounds are faced with the disadvantages of easy aggregation,large particle size and uneven distribution.Therefore,biomass with advantages of cheap,environmentally friendly,high nitrogen content was used as nitrogen source to provide anchor and inhibit the aggregation of metal particle.Hence,a series of Co-N-C was prepared through different pretreatment methods with casein rich in amino acid as nitrogen source,metal porphyrin with high catalytic activity as metal source.Specific research contents are as follows:1?By impregnating cobalt porphyrin on the surface of casein and pyrolyzed at 500 ? to prepared a series of Co-N-C with different content of metal.The results show that the casein can effectively increase the nitrogen content,improve the dispersion of the metal particles and reduce the particle size.The biomass derived Co-N-C showed superior catalytic performance in aerobic oxidation of ethylbenzene.When the loading of cobalt porphyrin was 0.5 g,the catalyst gave highest catalytic performance with ethylbenzene conversion rate reached 25%.The catalyst not only showed good catalytic activity in aerobic oxidation of a series of C-H bonds,but also exhibited high stability.The catalytic performance of the catalyst was not significantly reduced after 5 cycles.2?The homogeneous solution with well dispersed casein and cobalt porphyrin was prepared through dissolving nitrogen and metal precursor into ionic liquid.A series of biomass derived Co-N-C was prepared by calcinating the solution at different temperatures.The results show that the optimal calcination temperature was 500 ?,with ethylbenzene conversion rate reached 35%.The catalytic performance of the catalyst decreases with the increase of calcination temperature,which may be due to the agglomeration of metal particles.The Co-N-C particles prepared by one pot method are more uniform than that of immersion method,with the average particle size of 4.6 nm.The catalytic activity of the catalyst in aerobic oxidation of C-H bond was improved than Co-N-C prepared by impregnation.3?The B and N Co-doped Co-B-N-C was prepared through using 1-buty 1-3-methylimidazolium fluoboric acid salt as boron precursor,amino acid as nitrogen precursor,cobalt porphyrin as metal precursor.The catalytic performance of the catalyst has been further improved under the promotion of B element.When phenylalaninen used as nitrogen source,the corresponding Co-B-N-C showed the highest catalytic performance with ethylbenzene conversion rate reached 40%.The catalyst exhibited high activity in aerobic oxidation of C-H bond.The stability was also improved,and the catalytic effect was not significantly reduced after 10 cycles.