Chain Mail for Catalysts.

Encapsulating transition-metal nanoparticles inside carbon nanotubes (CNTs) or spheres has emerged as a novel strategy for designing highly durable nonprecious-metal catalysts. The stable carbon layer protects the inner metal core from the destructive reaction environment and thus is described as chain mail for catalysts. Electron transfer from the active metal core to the carbon layer stimulates unique catalytic activity on the carbon surface, which has been utilized extensively in a variety of catalytic reaction systems. Here, we elaborate the underlying working principle of chain mail for catalysts as well as the key factors that determine their catalytic properties, and provide insights into the physicochemical nature of such catalyst architectures for further application of the strategy in rational catalyst design.