Engineering Yolk–Shell Co-CN@SiO₂ Nanoreactors for Efficient Selective Hydrogenation of Aromatic Aldehydes

The increasing demand for sustainable and efficient catalytic processes has driven the development of advanced nanoreactors. In this study, we present a sophisticated Metal–organic framework (MOF)-template-mediated approach to synthesize yolk–shell Co-CN@SiO2 nanoreactors, where Co nanoparticles were supported on carbon nitride (C–N) nanosheets as the core encapsulated within a nanoporous SiO2 shell. This yolk–shell structure with confined cavities can provide a high surface area and overcome challenges such as Co nanoparticle sintering and mass transport limitations, resulting in superior catalytic performance. Remarkably, these nanoreactors achieved a 99% yield of benzyl alcohol from benzaldehyde hydrogenation under base-free conditions. Moreover, the influence of calcination temperatures on the structural evolution of the Co-based silica nanoreactors was explored, revealing the critical role of synergistic interaction between C–N and Co nanoparticles in boosting catalytic activity. Density functional theory calculations were conducted to investigate the adsorption energies of reacting species on the catalyst, providing mechanistic insights into the enhanced hydrogenation activity of the Co-CN@SiO2. This work offers valuable insights into the rational design of advanced nanoreactors for various catalytic applications, particularly in the field of green chemistry and sustainable synthesis.