Selective Discrimination between CO and H₂ with Copper–Ceria-Resistive Gas Sensors

Abstract

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 energydispersive 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 .

A Comparative Study of the Electronic Transport and Gas-Sensitive Properties of Graphene+, T-graphene, Net-graphene, and Biphenylene-Based Two-Dimensional Devices

“…Stability of the adsorption configurations is assessed by measuring the adsorption energy ( E ad ) of the system − before and after adsorption of gas molecules, as follows: E ad = E total − E substrates − E gas Here, E total represents the total energy of the system after adsorption of small gas molecules, and E substrates and the E gas are the energy of original graphene+, T-graphene, net-graphene, and biphenylene and individual gas molecules, respectively. The current difference (Δ I ) is employed to evaluate the gas capture ability, which was defined as normalΔ I = | I normala − I normalb | where the I a and I b are the currents of the system with and without gas molecules, and the larger the value of ΔI , the higher the sensitivity.…”

Chemiresistors Based on Hybrid Nanostructures Obtained from Graphene and Conducting Polymers with Potential Use in Breath Methane Detection Associated with Irritable Bowel Syndrome

“…Using an adequate choice of sensing material, resistive gas sensors can be tailored to detect a specifically targeted gas, in our case methane [53][54][55]. On the other hand, they have reduced selectivity and longer response and recovery times [55][56][57]. Factors such as temperature and humidity may impact the performance of resistive gas sensors [58].…”

A Mini-Review on Metal Oxide Semiconductor Gas Sensors for Carbon Monoxide Detection at Room Temperature

“…Infrared CO sensors have a large volume and high price. Compared with their counterpart like an electrochemical CO sensor, semiconductor CO sensors have several advantages such as low cost, high robustness, and a long lifetime, thus are widely applied in CO monitoring [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Many semiconductors such as carbon nanotubes, metal oxides, and organic compounds have been studied for use in CO sensors [23][24][25][26].…”

“…Many semiconductors such as carbon nanotubes, metal oxides, and organic compounds have been studied for use in CO sensors [23][24][25][26]. Among all the semiconductor sensing materials, metal oxides are the cheapest and most stable ones [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. It is a trend to incorporate MOS CO sensors into mobile phones or other portable devices to facilitate CO measurement [27].…”