Chemically and thermally stable lanthanide-doped Y₂O₃ nanoparticles for remote temperature sensing in catalytic environments

Luminescent nanoparticles have great potential for remote temperature sensing. Mapping of high temperature profiles under harsh conditions that are common in chemical reactors requires new thermally and chemically stable (nano)probes. Here, we report temperature dependent luminescence of Yb³⁺/Er³⁺-, Dy³⁺- and Eu³⁺-doped Y₂O₃ nanoparticles (NPs). We have deposited these lanthanide-doped Y₂O₃ NPs on α-Al₂O₃, a non-porous catalyst support material. The NPs are strongly adsorbed on the surface and no sintering was observed upon heating to 900 K for 12 h. The high chemical and thermal stability of Y₂O₃ makes these nanoprobes ideal for sensing in catalytic environments. A systematic study of the three types of luminescent NPs reveals that the temperature dependent luminescence of Yb³⁺/Er³⁺, Dy³⁺ and Eu³⁺ serves different temperature ranges: lower T regime (300–800 K, accuracy < 5 K) for Yb³⁺/Er³⁺, intermediate T for Dy³⁺ (400–900 + K, accuracy < 15 K) and high T for Eu³⁺ (550–900 + K, accuracy < 12 K). The superior thermal and chemical stability of the Y₂O₃/α-Al₂O₃ host in combination with different luminescent lanthanide dopants results in a robust system that can be tailored to monitor temperatures in different regimes with the highest possible sensitivity.