This work describes the behavior of a matrix of nanosensors based on metal oxides (MOS) for detecting of methane and carbon dioxide (greenhouse gases) at room temperature. The materials used were tin oxide and zinc oxide nanoparticles. The sensors were deposited via dropcasting from aqueous solutions of MOS nanoparticles. Some of the sensors were doped with terbium to evaluate their catalytic properties, and to leverage their optical properties, exploring the possibility of an opto-resistive sensor. Measurements of both gases were taken at different concentrations and at 50% relative humidity to simulate real-world conditions as closely as possible. During the measurement process, the nanosensor matrix was illuminated with an ultraviolet lamp for two purposes: to promote gas adsorption and desorption on the material surface, achieving a quicker electrical response, and to excite the material with ultraviolet light to collect the subsequent photoluminescence (PL) emitted by it and observe the change that occurs in the presence of the target gases.
The results demonstrate that the sensors are capable of detecting both compounds, as there is a resistive variation when the sensor is exposed to these gases. However, there is no variation in the photoluminescence emitted by the material when excited with an ultraviolet lamp in the presence of methane.
