Influence of hydrogen on the thermoelectric voltage signal in a Pt/WOx/6H-SiC/Ni/Pt layered structure

Abstract

The possibility of detecting H₂ by registering the thermal electromotive force signal, which arises between the surfaces of 6H-SiC plates with a thickness of 400 μm, is established. The working surface of the plates is modified by deposition of a WO_x film and catalytic Pt. An ohmic contact (Ni/Pt) is created on the rear surface of the plate, and this surface is maintained at a stabilized temperature of 350°C. The temperature gradient through the plate thickness arises due to the cooling of the working surface with the air medium. The delivery of H₂ into this medium up to a concentration of 2% gives rise to a 15-fold increase in the electric signal, which considerably exceeds the Pt/WO_x/SiC/Ni/Pt system’s response registered in the usual way by measuring the current–voltage dependence. In this case, an additional power source for the registration of the thermal electromotive force is not required.