The impact of interfaces in the processing and properties of polycrystalline material is briefly discussed. The local properties of the interfacial layer are considered in terms of composition, structure and related properties that differ substantially from those of the bulk phase. It has been postulated that novel materials with desired properties for specific industrial applications may be processed through interface engineering rather than through bulk chemistry. This paper considers the impact of interfaces on the properties of materials for technological applications, such as electrochemical devices for reduction of greenhouse gases, through energy conversion and environmental monitoring. The procedures that may be applied for the modification of interfacial chemistry are considered.