Nanoporous Metal-Containing Nickel Phosphates: A Class of Shape-Selective Catalyst

摘要

The discovery of a large family of nanoporous aluminum phosphates in the early 1980s has generated widespread interest in non-aluminosilicate-based microporous materials, and there has been an enormous growth in the chemical diversity of open-framework inorganic materials in new compositional domains during the last decade. Commercial applications of open-framework materials continue to be dominated by the aluminosilicate zeolites, but attempts are being made to exploit some of the exciting properties of the newly discovered systems. Recent synthetic efforts have led to the discovery of many new phases, for example, V-P-O, Fe-P-O, Co-P-O and Zn-P-O. However, as is the case with most nonsilicate open frameworks, the poor thermal stability of these systems leads to the collapse of the pore structures on activation, thus rendering them unsuitable for applications that require porosity. The challenge, therefore, is to design a nanoporous system that is thermally stable with respect to chemical or structural degradation and can be applied in catalytic reactions that are carried out at relatively high temperatures. In this respect, the need for new classes of catalysts has led a quest for creating novel nanoporous materials that might also exhibit catalytic activity.