Selective Discrimination Between CO and H with Copper-Ceria-Resistive Gas Sensors

The production of hydrogen and the utilization of biomass for sustainable concepts of energy conversion and storage require gas sensors that discriminate between hydrogen (H) and carbon monoxide (CO). Mesoporous copper-ceria (Cu-CeO) materials with large specific surface areas and uniform porosity are prepared by nanocasting, and their textural properties are characterized by N physisorption, powder XRD, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The oxidation states of copper (Cu, Cu) and cerium (Ce, Ce) are investigated by XPS. The materials are used as resistive gas sensors for H and CO. The sensors show a stronger response to CO than to H and low cross-sensitivity to humidity. Copper turns out to be a necessary component; copper-free ceria materials prepared by the same method show only poor sensing performance. By measuring both gases (CO and H) simultaneously, it is shown that this behavior can be utilized for selective sensing of CO in the presence of H.