Selective Discrimination between CO and H 2 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 2 ) and carbon monoxide (CO). Mesoporous copper-ceria (Cu-CeO 2 ) materials with large specific surface areas and uniform porosity are prepared by nanocasting, and their textural properties are characterized by N 2 physisorption, powder XRD, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The oxidation states of copper (Cu + , Cu 2+ ) and cerium (Ce 3+ , Ce 4+ ) are investigated by XPS. The materials are used as resistive gas sensors for H 2 and CO. The sensors show a stronger response to CO than to H 2 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 2 ) simultaneously, it is shown that this behavior can be utilized for selective sensing of CO in the presence of H 2 .