Fabrication of Fe Single Atoms by Utilizing the Inherent Confined Space for Phenol Hydroxylation

Diphenol is a key chemical product, and the phenol hydroxylation reaction is an important route for the synthesis of diphenol. The Fe sites are well-known active centers for the phenol hydroxylation reaction, and the reaction activity depends on the dispersion of Fe sites; however, facile fabrication of highly dispersed Fe sites remains a big challenge. Here, we provide a simple method for the synthesis of Fe single-atom catalysts (SACs) by utilizing the confined space which exists in template-occupied SBA-15 (TOS). By simple solid phase grinding and subsequent calcination, the Fe precursor was easily introduced into the inherent confined space to form a Fe-O-Si structure. A total of 10 g of SACs can be synthesized easily and efficiently in a single pass via ball milling. The Fe SACs have been applied for the phenol hydroxylation reaction with significantly higher activity than comparison samples without inherent confined space.