화학공학소재연구정보센터
Catalysis Letters, Vol.94, No.3-4, 181-185, 2004
Determination of the electronic state and concentration of nickel in NiSAPO catalysts by magnetic measurements
A method to determine the electronic state and concentration of Ni in Ni-loaded silicoaluminophosphate (NiSAPO-n) where n denotes the structure type ( n = 47, 18, 34, 44, 56 and 17) is presented. The method involves measurements and analysis of the magnetization M versus magnetic field H ( up to 55 kOe at 2 K) and M versus temperature ( T = 2 - 300 K) data. The analysis yields spin S = 1/2 corresponding to Ni( I) state for lightly doped samples, whereas for higher doping, both Ni( I) and Ni( 0) are indicated. The concentration of Ni determined from these studies varies between the minimum of 0.2 wt% for the n = 47 sample to maximum of 1.75% for the n = 17 sample.