Beyond Ordered Materials: Understanding Catalytic Sites on Amorphous Solids

Abstract

Amorphous materials are widely used as components of solid catalysts and have been the subject of much applied research. In some instances, their catalytic performance is demonstrably superior to that of their crystalline counterparts, due in part to their greater flexibility. Amorphous or disordered phases can also be generated from crystalline phases under reaction conditions, and thus, ex situ observations of long-range order may provide an incomplete or misleading picture. Until recently, theorists and experimentalists have mostly neglected these important materials in fundamental studies, preferring instead to study “well-defined” (often crystalline) catalysts that are potentially more tractable and amenable to computational modeling of their structure–activity relationships. The amorphous materials were assumed to be simply nonuniform versions of compositionally similar materials with long-range order, having the same key features at short and medium length scales. In this Perspective, shortcomings ...