Nanostructured CeO2-C Derived from Ce-BDC Precursors for Room-Temperature Ammonia Sensing

The prompt and reliable detection of NH3 leakage at room temperature (RT) is considered important for safety assurance and sustainable production. Although chemiresistive NH3 sensors feature low cost and structural simplicity, their practical application is hindered by high operating temperatures and inadequate selectivity. Metal–organic frameworks (MOFs) and their derivatives offer a promising approach to address these limitations. In this work, Ce-BDC precursors with tunable particle sizes and crystallinity were synthesized by adjusting the raw material concentration. Controlled pyrolysis yielded a series of CeO2-C-X (X = 0.5, 1, 1.5, 2) materials with nanosized particles. Among them, the CeO2-C-1 sensor delivered a high response of 82% toward NH3 under 40% relative humidity at RT. Moreover, it possessed excellent selectivity, repeatability, and rapid response-recovery behavior compared with the other samples. CeO2-C-1 also remained stable under varying oxygen and humidity conditions, demonstrating high applicability. The superior sensing properties may be attributed to its high specific surface area and optimized mesoporous structure, which facilitated efficient gas adsorption and reaction. These findings demonstrated that precise control of MOF precursors and the structure in CeO2 nanomaterials was critical for achieving high-performance gas sensing and established Ce-MOF-derived CeO2 as a promising sensing material for NH3 detection at RT.