Potentiometric C2H4-Selective Detection on Solid-State Sensors Activated with Bifunctional Catalytic Nanoparticles

This work presents a solid-state ionic-based device to selectively detect C2H4 in car exhaust gases. The sensor consists of 8YSZ as the electrolyte and two electrodes: Fe0.7Cr1.3O3/8YSZ and LSM/8YSZ. The main aim of this work is to optimize the catalytic behavior of the working electrode to C2H4 and reduce cross-sensitivity toward CO and H2O. Several catalyst nanoparticles were infiltrated to tailor C2H4 adsorption and electrochemical oxidation properties while diminishing adsorption and conversion of other gas components such as CO. The infiltrated metal catalysts were selected, taking into account both adsorption and redox properties. Infiltration of Ti or Al, followed by a second infiltration of Ni, enabled the selective detection of C2H4 with low cross-sensitivity toward CO and H2O in a moist gas environment. Further insight into potentiometric C2H4 sensing is achieved by electrochemical impedance analysis of the electrodes activated with bifunctional catalysts.

Mechanism of Microwave Activation on Molybdenite

The effect of microwave activation on the properties of oxidation roasting for molybdenite was investigated under the protection of inert gas, and the specific surface area, the oxidation properties, lattice constant, microstructure, and shape of molybdenite were analyzed and characterized by a laser particle size analyzer, thermogravimetry (TG), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results show that microwave activation could effectively reduce the residual amount of sulfur in the molybdenum calcine and decrease the average particle size of molybdenite while increasing the specific surface area of molybdenite. On increasing the microwave activation power, the crystal cell volume and grain size of MoS2 reduced, and the microstrain increased slightly. At the same time, the surface shape of molybdenite became looser, but the layered structure is not changed. In addition, the oxidation property changed significantly; microwave activation promoted the oxidation reaction of molybdenite above 538 °C, and the rate of weight loss increased from 6.177% to 7.718% at 620 °C.