Acta Phys. -Chim. Sin. ›› 1996, Vol. 12 ›› Issue (07): 609-614.doi: 10.3866/PKU.WHXB19960707

• ARTICLE • Previous Articles     Next Articles

Studies on the Synthesis and structure of Pd Clusters Encaged in Y-zeolite

Zhang Wan-Jing,Ji Tian-Hao,Meng Xian-Ping,Liu Ying-Jun,Lin Bing-Xiong   

  1. Institute of Physical Chemistry,Peking University,Beijing 100871
  • Received:1995-12-09 Revised:1996-02-08 Published:1996-07-15
  • Contact: Zhang Wan-Jing

Abstract:

Pd clusters encaged in Y-zeolite (Pd0Y) have been prepared by means of exchanging zeolite HY with [Pd(NH3)4]2+ under microwave radiation. The product formed was deaminized by heating, washed sufficiently with de-ionized water and reduced with hydrogen. The crystal phase diffraction of Pd was not found in the XRD spectrogram of Pd0y. According to polycrystal X-ray diffraction data. Radial Electron Distribution Function (REDF) of Pd0Y was calculated to elucidate the structure of Pd cluster. The results show that the Pd clusters are of the Al type closely packed arrangement. The dimension of them is about 12 Å. They are encaged in the supercage of zeolite Y. Their occupancy on the supercage is as small as 0.06 so that the framework structure of zeolite Y is unchanged. Therefore, the high dispersing Pd cluster aggregating in supercage exhibit strong catalytic effect. The CO-conversion of Pd0Y with Pd 0.72% and 6.13% (in mass fraction) is 67 % and 100 % (in volume fraction) respectively. Evaluation conditions:
mixed gas containing 0.02% CO and air,
space velocity 3000 h-1,
reaction temperature 0 ℃.

Key words: Y-zeolite, Synthesis;Structure, Pd cluster, Radial Electron Distribution Function