Interface Oxygen Vacancy‐Enhanced Co₃O₄/WO₃ Nanorod Heterojunction for Sub‐ppm Level Detection of NO_x

Abstract

In this work, we developed and optimized a cobalt oxide/tungsten oxide (Co3O4/WO3) p‐n heterojunction for NOx detection. Field emission scanning electron microscopy showed that the WO3 nanorods were embellished with Co3O4 nanostructure. X‐ray photoelectron spectroscopy revealed the presence of oxygen vacancy on the Co3O4 coupled with WO3 heterojunction. Compared to bare WO3 and pure Co3O4, the Co3O4/WO3 heterojunction sensor showed significant sensitivity to NOx at 200oC. The sensor exhibited higher linearity from 0.4 to 10 ppm of NOx, with a sensing response of 4.4% to 93%. The NOx sensitivity of the Co3O4/WO3 heterojunction sensor was 9‐fold higher than that of the pure WO3 sensor. Even at a high humidity (84%) environment, the Co3O4/WO3 heterojunction sensor demonstrated high NOx sensitivity. The sensor maintained remarkable stability measured for up to 4 weeks. We additionally discussed the possible NOx sensing mechanism of the Co3O4/WO3 heterojunction.This article is protected by copyright. All rights reserved.

Glucose-Assisted Synthesis of Porous, Urchin-like Co3O4 Hierarchical Structures for Low-Concentration Hydrogen Sensing Materials

“…The asymmetric O 1s peak (Figure 4c) can be fitted and differentiated into three peaks, corresponding to lattice oxygen (529.8 eV), oxygen vacancies (530.2 eV), and chemically adsorbed oxygen (531.3 eV) [22]. The proportion of oxygen vacancies was calculated to be 24.7%, which is beneficial for oxygen adsorption and dissociation on the material surface [23]. N2 adsorption-desorption isotherms were tested to investigate the specific surface area and pore structure of the obtained Co3O4.…”

Constructing Z-Scheme WO3–CeO2 Heterojunctions for Selective Sensing of NO2 or Acetone Gas under UV Light Irradiation

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