Study On Prepartion And Properties Of Polyhedron Hollow Nano-catalyst Based On MOF Structure

As a kind of new energy conversion device,zinc-air battery has high conversion efficiency,which can meet the needs of development and environment of future.But the key to its development is the electrode catalyst material.The precious metal catalyst has good performance,but the price is more expensive and short of the reserves;on the other hand,generally a single precious metals generally show good catalytic performance for a certain reaction,can't satisfy the zinc air battery ORR and OER two reactions.Therefore,the main solutions to these problems are:Using different non-noble metal catalysts to synthesize bimetallic catalysts,this can reduce the cost of the catalyst and also can satisfy the catalytic effect of different reactions.In addition that,to synthesis of bimetallic catalyst and carrier of the special morphology of compound preparation of compound catalyst,due to the topography effect and synergy between metal and the morphology improves the performance of the composite catalyst.In this paper,a series of compound catalysts of bimetallic compounds were synthesized by adding different metals and anions with special morphological ZIF-67 as carrier,aim to reduce the cost of catalyst and improve the catalytic performance of catalyst.The effects of different metals and anions on catalytic performance were studied systematically.The main contents of this paper were summarized as follows:Firstly,the cobalt ions of obalt nitrate hexahydrate as the center ion,2-methyl imidazole for organic ligand was synthesized dodecahedron ZIF-67 as a template,add non-noble metal Ni and Mg,then calcined the sample will get hollow dodecahedron sample with a fold surface morphology MgNiO₂/CoNC composite catalyst.The structure,morphology,element composition and other physical characterization of the synthesized catalyst were performed,and ORR and OER electrical performance and stability were characterized by electrochemical workstation.The results show that the morphology of the surface of the catalyst is drape hollow dodecahedron structure,the particle size is about 500-600 nm,the metal elements Mg and Ni were evenly dispersed on the surface of shell at the same time.Electrochemical characterization indicates that the catalyst has good ORR and OER electrochemical activity and stability.Secondly,with ZIF-67 as the template,non-precious metal Ni was added.On this basis,with TAA as sulfur source,and non-metallic element sulfur was added.At last we synthesized the bimetallic sulfide NiCoS catalyst.The physical and electrical properties of the catalyst were characterized by morphology and structrue.The results showed that the synthesized catalyst was hollow dodecahedral structure with a folding structure on the surface,the size was about 600 nm,and the elements Ni and S were evenly dispersed on the shell layer surface of the catalyst.The electrochemical test results showed that the the catalyst exhibited excellent ORR,OER and HER performance.and the results of the Zn-air battery test showed that the charging and discharging had lower overpower potential and better stability.Thirdly,with ZIF-67 as the template,non-noble metal Ni was added.On this basis,with NaH₂PO₄ as the phosphorus source,the non-metallic element phosphorus was added by calcining method,last the bimetallic phosphide catalyst NiCoP was obtained.Physical characterized results showed that the obtained catalyst is hollow dodecahedron with fold structure on the surface,the size is about 600 nm.The elements analysis showed that the elements Ni and P evenly dispersed on the shell of the catalyst.The electrochemical test results showed that the catalyst exhibited excellent ORR,OER and HER performance and can serve as trifunctional catalyst.In this paper,inder to improve the activity and diversification of the catalysts,we used ZIF-67 as the template,with different non-noble metals and S,P and other elements as doped elements.The non-noble metal composite catalysts were synthesized.The synthesized catalysts had good electrocatalytic activity and diversity.It solved the problem of single catalyst performance.By means of scientific characterization,we studied the influence of different elements on the activity of catalyst.