Activation And Properties Of Metal-organic Framework(Cu-MOF)by Atmospheric Pressure Cold Plasma

Metal-organic frameworks(MOFs),a new kind of porous material,have been used in catalysis,gas absorption and separation and so on due to their high specific surface areas,etc.In preparing MOFs,it is necessary to take a process of activation to remove the guest molecules within their new formed structure.Generally adopted methods for activating MOFs are heating or solvent exchange combination with heating,which are noted as thermal treatment method and solvent exchange method,respectively.The effect of temperature has been discussed for thermal treatment,while the atmosphere has been overlooked.In addition,solvent exchange method is time-consuming and has to resort to organic solvents such as chloroform and methanol,which may be contaminated and poisonous.In this work,we firstly prepared a kind of Cu-MOF and its crystalline,pore structure,and morphology were characterized by XRD,BET,SEM,respectively.The results show that the prepared Cu-MOF has a BET value of 1102.9m2·g-1.The Cu-MOF shows an octahedron structure with a size of about 10?m,and it is thermally stable under the temperature of 300 oC.Secondly,the effects of activation temperature and atmosphere were investigated based on prepared Cu-MOF.The results show that the activation temperature has significant effects on the structure of Cu-MOF and its catalytic activity towards CO oxidation,and it is less effective when the activation temperature is too low or too high.And the effect of activation atmosphere is even more far-reaching when activated at the optimized temperature.Ar,O2,CO standard gas(mixture of 1%CO,20%O2 and 79%N2)and H2 were adopted to investigate the effect of activation atmosphere.The catalytic activity of Cu-MOF would be improved when using O2 or CO standard gas,while Ar and H2 are both less effective.Our study shows that the optimized activation temperature and atmosphere are 240 oC and CO standard gas.Furthermore,activating Cu-MOF with cold plasma is also studied in this work,and Cu-MOF supported transition metals were prepared to investigate the effects of transition element and amount of support.The results show that(1)cold plasma is helpful to reduce the initial reaction temperature of Cu-MOF for CO oxidation;(2)supporting with different transition metals would vary the catalytic activity of Cu-MOF,and Fe is the best among the transition metals of Fe,Co,Ni,Cu and Zn,and the optimized amountt is 7%.