Augmented MOF-ZnO nanostructure gas sensing capabilities for ppb-level n-butanol detection by RE (Ce, Eu, Er) incorporation and UV irradiation

n -Butanol, a volatile organic compound with relatively low toxicity, requires precise detection for public health and environmental safety. In this research, metal-organic framework (MOF)-ZnO nanostructures (zinc oxide nano-materials with the utilization of metal-organic frameworks as precursors) doped with rare earth elements (Ce, Eu, and Er) were synthesized via a homogeneous co-precipitation route. The produced samples were comprehensively characterized employing X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy to evaluate the morphological, structural, and optical characteristics. The gas-sensing capabilities of the RE (Ce, Eu, Er)-ZnO series of sensors were subsequently assessed in comparison to those of pristine MOF-ZnO by adjusting the doping type and ratio of rare earth elements to optimize the sensor performance. Among the materials tested, the 0.08 wt% Eu-ZnO sensor exhibits the best-of-breed sensitivity and selectivity, achieving the impressive response value of 616.11 and the detection limit of 361.52 ppb working at 230 °C under 100 ppm of n- butanol exposure, this achievement attains 8.7 times greater than that of pristine MOF-ZnO (70.72). Moreover, with the aid of ultraviolet excitation, the performance of the 0.08 wt% Eu-ZnO sensor is further enhanced, with the sensitivity response elevating to 1000.65 and 4.3 times greater than that of pristine MOF-ZnO (231), leading to the lower detection limit of 259.70 ppb at 220 °C. These findings underscore the significant potential of rare earth incorporation and UV irradiation playing as the synergistic strategy to augment the gas-sensing capabilities, preeminently in the detection of low-concentration volatile organic compounds.