CO Oxidation Over The Metal-organic Frame Works(Cu-BTC)

Metal organic frameworks(MOFs) formed by the self-assembly of metal ions andorganic ligands are a new type of functional material, which contain ordered andregular pores, and shows potential application in the areas of gas adsorption,separation, catalysis and etc. Cu-BTC, one of the most studied MOFs, has been usedin several liquid phase reactions, but gas solid catalytic reactions over Cu-BTC arescarce. Furthermore, the role that the unsaturated metal sites within the framework ofMOFs in catalytic reactions is not fully understood.The synthesis methods and applications in catalysis of MOFs have beenreviewed in this paper. The catalytic performance of Cu-BTC in gas-phase reactions isstudied using CO oxidation as a probe reaction. The main research contents are asfollows:(1) The thermal stability of Cu-BTC was studied in detail. The Cu-BTC sampleswere treated at different temperatures in order to reveal the thermal stability of theframework. The characterization results of XRD, TG/DSC, BET, SEM and in-situFTIR showed that the framework of Cu-BTC kept unchanged when it was treatedbelow280℃.(2) The catalytic activity of Cu-BTC was evaluated using CO oxidation as amodel reaction. It was found that the activation temperature of the Cu-BTC sampleshowed a significant effect on the catalytic activity of CO oxidation. The higher theactivation temperature, the higher is the activity of Cu-BTC. The Cu-BTC sampleactivated at250℃showed the best catalytic activity, for which the CO completeconversion temperature being170℃. The characterization results of DRIFTS, XRD,TG/DSC, BET and SEM showed that the open metal sites within the framework ofCu-BTC are the active centers for CO oxidation. The Cu+-CO species formed whenCO molecules adsorbed on the open copper sites are the active intermediate of COoxidation. The more open metal sites within the Cu-BTC framework, the higheractivity of the Cu-BTC will be shown.(3) Two inorganic components, Cu(NO3)2and Cu2O, which can improve the COoxidation, were loaded on Cu-BTC by impregnation. The catalytic activities ofCu(NO3)2/Cu-BTC and Cu2O/Cu-BTC for CO oxidation were also evaluated.