Pd-Te alloy inside hollow silica nanospheres for semi‑hydrogenation of dehydrolinalool to linalool

Enhancing alkenol selectivity during catalytic alkynol hydrogenation is of particular importance for synthesis of fine chemicals. Herein, we design a reverse microemulsion approach to synthesize PdTe alloy nanoparticles encapsulated inside hollow porous silica nanospheres (Pd-Te@HPSNs) for semi‑hydrogenation of dehydrolinalool (DHL) to linalool (LN). Compared with monometallic Pd@HPSNs, the PdTe@HPSNs catalysts with an optimized Pd/Te ratio demonstrate dramatically improved LN selectivity in hydrogenation of DHL. Under mild conditions of 45 °C and 0.1 MPa H₂, LN yield of 96.5 % over PdTe@HPSNs was achieved within 50 min at a DHL/Pd molar ratio of 256/1. Importantly, high LN selectivity was maintained even upon a prolonged reaction time. Comprehensive characterizations reveal that Pd alloying with tellurium induces a strong electronic interaction (charge transfer from Pd to Te), leading to an electron-deficient Pd state. This electronic modification, coupled with the geometric effect of isolating contiguous Pd ensembles by Te atoms, greatly improves the alkenol selectivity. The PdTe@HPSNs catalysts maintain >95 % LN yields during recycling experiments, illustrating excellent reusability due to the protective silica shells. This study provides a pioneer work to use PdTe alloy for design of selective hydrogenation catalysts, and a new example to address the long-standing alkene selectivity challenges in alkyne hydrogenations.