Studies of the Cataluminescence of Benzene Homologues on Nanosized γ–Al2O3/Eu2O3 and the Development of a Gas Sensor for Benzene Homologue Vapors

The cataluminescence (CTL) of benzene and the benzene homologues toluene and xylene on nanosized γ–Al2O3 doped with Eu2O3 (γ–Al2O3/Eu2O3) was studied and a sensor of determining these gases was designed. The proposed sensor showed high sensitivity and selectivity at an optimal temperature of 432 oC, a wavelength of 425 nm and a flow rate of 400 mL/min. Quantitative analysis was performed at the optimal conditions. The linear ranges of CTL intensity versus concentration of the benzene homologues were as follows: benzene 2.4~5000 mL/m, toluene 4.0~5000 mL/m and xylene 6.8~5000 mL/m, with detection limits (3σ) of 1.8 mL/m, 3.0 mL/m and 3.4 mL/m for each one, respectively. The response time of this system was less than 3 s. The coexistence of other gases, such as SO2, CO and NH3, caused interference at levels around 11.7%, 5.8% and 8.9% respectively. The technique is a convenient and fast way of determining the vapors of benzene homologues in air.