Oriented zeolite growth on surfaces achieved

Abstract

The first oriented growth of molecular sieve (zeolite) crystals on surfaces has been achieved by graduate student Sue Feng and chemistry professor Thomas Bein of Purdue University. The work, reported in last week's Nature [ 368 , 834 (1994)], represents a new thrust in the synthesis of zeolitic materials. It could potentially lead to the ability to achieve greater control over physical and chemical processing with controlled-porosity media. In their research, Feng and Bein deposited an analog of zeolite X by crystallization on gold-coated silicon substrates modified with metal phosphonate multilayer films. The organophosphonate films promote nucleation and growth of the zinco-phosphate zeolite from the synthesis mixtures. Scanning electron micrographs show that single layers of the zinco-phosphate crystals are produced, with more than 90% of them having their (111) faces oriented to the substrate. The nearly perfect orientation of the crystals is further supported by the evidence of diffraction patterns. ...