Low temperature triethylamine sensing based on annealed amorphous cobalt tin oxide nanoboxes with tunable oxygen vacancies

The development of triethylamine (TEA) sensors with high sensitivity and selectivity is of great significance for realizing multi-field applications such as environmental monitoring and industrial safety. In this study, a novel and high-performance TEA sensor strategy based on single-component amorphous materials is proposed. By employing CoSn(OH)₆ nanocubes as precursors, amorphous hollow CoSnO₃ nanoboxes were successfully synthesized via an alkali etching process followed by a controlled annealing procedure. The results showed that annealing temperature accurately regulated the degree of amorphous and oxygen vacancy concentration of the material. Based on the analysis of characterization test results, it was confirmed that the unique hollow nanobox structure formed through alkali etching significantly enhanced the specific surface area of the pristine nanocube, reaching up to 262.4 m²/g. Gas sensitive tests demonstrated that the response value (Rg/Ra = 24.5) of the HCSO-200 sensor to 50 ppm TEA at low operating temperatures (120^oC) was nearly 4.2 times higher than that of crystalline material, with excellent repeatability and long-term stability. Further mechanistic studies showed that the excellent TEA sensing performance of the HCSO-200 material could be attributed to its amorphous structure, hollow morphology, and optimized oxygen vacancy concentration by controlling annealing temperature. This work not only provides an efficient one-component sensing material for TEA detection, but also broadens the idea of other amorphous semiconductor materials for gas detection.