Nanoconfined Growth of Carbon-Encapsulated Cobalts as Cocatalysts for Photocatalytic Hydrogen Evolution

Transition metal nanoparticles encapsulated in carbon nanostructures (M@Carbon, M = Fe, Co, Ni, et al.) exhibit excellent catalytic performance toward the hydrogen evolution reaction (HER). However, their application as HER cocatalysts for photocatalytic hydrogen production is greatly hampered by their random growth nanostructures with rather big overall size (e.g., nanotube structure with length of 5-50 mu m). Herein, a nanoconfined assembly strategy is well developed for the textural engineering of Co@Carbon with an optimized nanostructure for photocatalysis. The spatial compartmentalization and physical confinement of precursors within the silica aerogel kinetically control the core-shell nanostructure assembly and facilitates the synthesis of Co@Carbon with controllable morphology and reduced particle size (similar to 30 nm), making Co@Carbon a promising HER cocatalyst for photocatalytic hydrogen evolution. Furthermore, this nanoconfined assembly strategy is a general approach that can be widely applied for textural engineering of other transition metal-embedded or their alloy-embedded carbon structures for photocatalysis or other energy-related applications.