Synergistic Cu/CeO2/Halloysite Nanotube Catalysts for Temperature-Programmable Biomass Valorization

A bifunctional Cu/CeO2/halloysite catalyst was rationally constructed via strong electrostatic adsorption to enable switchable conversion of furfural into either furfuryl alcohol or isopropyl furfuryl ether. Highly dispersed Cu nanoparticles are anchored on CeO2 nanoislands supported by acid-etched halloysite nanotubes, creating a unique “support–adjuvant–active site” synergy. This architecture facilitates H2 activation and tandem hydrogenation–etherification, allowing precise temperature-controlled pathway selection. Under mild conditions, furfural hydrogenation to furfuryl alcohol proceeds via a low-energy barrier (0.9 eV) with a stable intermediate, whereas etherification requires overcoming a significant barrier (1.6 eV), becoming favorable only at elevated temperatures. In situ FTIR, kinetic studies, and DFT calculations reveal the mechanistic origin of this selectivity. The catalyst displays high activity, tunable selectivity, and robust recyclability, providing a versatile strategy for controlling reaction pathways in the valorization of biomass-derived platform molecules.