Adsorption of nitric oxide and temperature programmed desorption on nonstoichiometric nickel–copper manganites

Abstract

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. AbstractThe interaction of nitric oxide with nonstoichiometric nickel±copper manganites has been investigated by adsorption and temperature programmed desorption (TPD) experiments. Nitric oxide was found to adsorb molecularly at room temperature on such oxides. Reversibly and irreversibly adsorbed NO molecules were evidenced. The amount of reversibly and irreversibly adsorbed NO increased with the nickel content but decreased with the copper one. Moreover, the ratio reversible/irreversible increased with the copper content of the oxides. TPD experiments indicated that adsorbed NO desorbs at low temperature (below 2008C) mainly as NO molecules (70±90%). The balance consists of N 2 O, a part of which desorbs below 2008C and the rest above 2508C. The area of the peak corresponding to the desorption of nitrous oxide at high temperature is far much larger for copper-free oxides.

Heterogeneous Catalytic Evaluation of Potentiometric La2CuO4 Sensor Electrodes

“…Additionally, the adsorption behaviors of the gases on the surface of the electrodes play a significant role. The adsorption of gases forms charged species at the surface of the electrode (10,11), leading to an accumulation or depletion of electrons, which in turn can create an electric field across the electronically blocking electrolyte. La 2 CuO 4 demonstrates promise as a material for a sensing electrode to explore this mechanism.…”

Infrared and X-Ray Photoemission Spectroscopy of Adsorbates on La[sub 2]CuO[sub 4] to Determine Potentiometric NO[sub x] Sensor Response Mechanism

“…7,[9][10][11][12][13] The adsorption of gases forms charged species at the surface of the electrode, leading to an accumulation or depletion of electrons, which, in turn, can create an electric field across the electronically blocking electrolyte. 14,15 La 2 CuO 4 demonstrates promise as a material for a sensing electrode to explore this mechanism. The compound is catalytically unresponsive to the NO → N 2 and NO → NO 2 reactions in the presence of oxygen, 16 and thus the contributions from these catalytic or electrochemical reactions during NO x sensing are minimal.…”

Humidity-Tolerant Ultrathin NiO Gas-Sensing Films

“…Thus, it can be inferred that, while the overall resistance in their n-type SnO 2 samples was dominated by bulk donor defects, water had a strong effect on the overall resistance. One promising candidate p-type sensing material, NiO, which behaves as a p-type semiconductor due to the presence of nickel defects within the material even at moderate temperatures (above 150 K), has a complex and variable oxygen desorption, , which, due to the importance of surface oxygen species in mediating gas-sensing reactions, could lead to the evolution of temperature-dependent specific analyte interactions and hence selective response. Due to these interesting material characteristics, we were interested in exploring p-type semiconducting metal oxides, and in particular NiO, for selective and humidity-tolerant gas sensing.…”