Fabricating Ce(DS)2H4AlW12O40 as a single-cluster heterogeneous catalyst for highly efficient conversion of cellulose to 5-HMF in water and in biphase

Producing 5-hydroxymethylfurfural (5-HMF) through cellulose degradation using highly efficient catalytic reactions represents a promising yet challenging strategy to address the need for fossil resource replacement. In this study, amphiphilic triple-heteropolyacid (HPA), Ce (DS)2H4AlW12O40 (abbreviated as Ce (DS)AlW12, where DS is a representative dodecyl sulfonate surfactant) was designed and fabricated via the linkage of Ce3+ to anionic surfactant and polyanion. This versatile catalyst could assemble into nano-micelles in aqueous media, where heteropolyanions can locate on the surface of the micellar sphere, isolatedly as uniformed active sites, i.e. single-cluster, which was linked with Ce (DS)+ inside the sphere to form a hydrophobic core being determined by characterization and Molecular Dynamic (MD) simulations. During the catalyzing reactions, the DS groups adsorb cellulose, the fully exposed polyanions and Ce3+ provide double-active centers of Brønsted (B) and Lewis (L) acids in single-molecular model, and the hydrophobic cores extract and protect the product. These advantages enabled Ce (DS)AlW12 to catalyze the conversion of cellulose into 5-HMF with a high selectivity for 63.7 % at 150 °C for 2 h in water. This work bridges the gap between heterogeneous, hierarchically assembled structures, and uniformly dispersed catalysis, providing an effective strategy for designing amphiphilic triple-HPA single-cluster catalysts to enable efficient 5-HMF production in aqueous systems. Furthermore, Ce (DS)AlW12 exhibited versatile functionality in the cascade conversion of cellulose in the biphasic system, notably achieving an 83.8 % yield of 5-HMF at 150 °C within 2 h.