Half-cell probes with Au and Au that was covered partially or completely with the VWT-catalyst (applied by brushing) were used.Figure 1.Schematic setup of the device. (a) Sensor-like setup. (b) Half-cell type setup.The setup for half-cell measurements is illustrated in Figure 2. Main parts of the half-cell setup were two stainless steel cylinders, each with a gas inlet and outlet and joined together by a mica seal. Both gas atmospheres were separated gas tightly by the mica seal and the half-cell probe itself, so that both electrodes could be exposed to different gas compositions. The RE was in contact with the reference gas atmosphere whereas the SE was exposed to the measuring gas. Platinum wires were used as contact leads. The entire half-cell setup was mounted into a chamber furnace which was heated up to operation temperature.

The temperature at the half-cell probe was monitored and adjusted to 550 ��C by two thermocouples (not shown in Figure 2). A temperature gradient of 5 K at the maximum was observed across the half-cell specimens.Figure 2.Schematic setup for half-cell measurements with half-cell probe ��measuring gas, sensing electrode (SE), VWT, Au | YSZ | Au, reference electrode (RE), reference gas��.2.2. Measurement of Sensor and Half
A solid-state wave gyroscope can be used to measure the angular velocity of a rotating body based on the inertia effect of the standing wave in two vibration modes of the axisymmetric resonator, which have advantages, such as small size, high operation accuracy, low cost, low power consumption, good shock resistance, and long life [1,2].

Axisymmetric vibratory structures with piezoelectric, magnetic or electrostatic actuators are widely used in vibratory gyroscopes, such as hemispherical resonator gyros (HRG), cylindrical resonant gyros (CRG), disk resonant gyros (DRG) and so on [3]. These structures are always activated and sensed by methods, including electromagnetics, electrostatics and piezoelectricity [4]. Symmetric vibratory structures with piezoelectric, magnetic or electrostatic actuators are widely used in vibratory gyroscopes, such as hemispherical resonator gyros (HRG), cylindrical resonant gyros (CRG), disk resonant gyros (DRG) and so on [3]. These structures are always activated and sensed by methods, including electromagnetics, electrostatics and piezoelectricity [4].

The hemispherical resonator gyroscope (HRG) was developed rapidly in Delco, Litton, and Northrop Grumman Co. [5], which has achieved inertial navigation performance levels and been used Batimastat for spacecraft stabilization, precision pointing, aircraft navigation and strategic accuracy systems. Innalabs Holding manufactured the Coriolis vibratory gyroscope (CVG) with a metallic cylindrical resonator (tactical grade) [6], and Watson industries designed the vibrating structure gyroscope (VSG) with a piezoceramic cupped structure (rate grade) [7].