文档介绍：Nanostructured Catalytic Materials: Design and Synthesis
N
Hua Chun Zeng
National University of Singapore, Singapore
INTRODUCTION With the emphasis on catalytic prospect, the objective of
this article thus aims at introducing various design and
Natural and manmade catalytic materials are among the synthesis strategies for this new class of materials. Future
oldest ‘‘nanostructured materials’’ known long before the challenges and research directions in this area will also
era of nanoscience and nanotechnology. The classic het- be addressed.
erogeneous catalysts consist of active nanoscale metal
component(s) and solid carriers,[1] namely, ‘‘inert’’ oxide
supports such as alumina, silicates, or magnesium oxide, DESIGN AND SYNTHESIS
to increase the reaction surface area and metal utilization. OF NANOSTRUCTURED
Conventional processing techniques for fabrication of CATALYTIC MATERIALS
supported catalysts contain one or more of the following
steps: impregnation, precipitation, coating, rewashing, Because of the advances in nanostructured catalytic ma-
ion-exchange, pulverization, dying, and calcination, etc.[2] terials and assembling methodologies, we may have to
Nanoscale metal clusters or particles can be thus formed reexamine the roles of ponent in the traditional
on the oxide carriers after these processes. It is now well heterogeneous catalysts and redevelop the technology. In
known that the particle size, position, and fact, a practical solid catalyst is normally not a simple
structure (shape) of nanoscale catalysts determine the pound, but a anized po-
ultimate catalytic activity and selectivity. For example, it nent materials system (., ponents and car-
has been demonstrated that the activity of TiO2-supported rier). In this regard, a modern view of solid catalysts is
gold particles is very sensitive to their size (2 to 3 nm) in different from the traditional one. anized assembly
the CO oxidation reaction with oxygen at ambient con- of