THE ROLE OF ANION IN THE PREPARATION OF NICKEL-CATALYST DETECTED BY TPR AND FTIR SPECTRA

The role of NO3- anion in the preparation of nickel catalysts detected by temperature-programmed reduction (TPR) and Fourier transform infrared spectroscopy was studied. Thermogravimetric analysis-mass spectrometry, X-ray photoelectron spectroscopy, and BET surface area were also used to evaluate the effect of calcination temperature. The role of NO3- anion is one of the key factors which determine the activities and properties of the prepared catalysts. Two reduction peaks, NO3- anion and NiO, of TPR were obtained for nickel catalyst drying at 110 degrees C. The results indicated that the reduction of NO3- anion occurs at 278 degrees C, and then nickel nitrate converts to Ni2O3 under hydrogen atmosphere. Nickel nitrate decomposed into NiO only and exhausted both NO and NO2 when it was calcined in air. On the basis of the results of BET, both surface area and pore volume of catalysts slightly increased and then decreased with calcination temperature. The average pore size was almost constant when calcination temperature was less than 1100 degrees C, after which it significantly increased.