Surface Modulation of Co₃O₄ Yolk-Shell Spheres with Tungsten Doping for Superior Acetone Sensitivity

This study introduces a promising technique to enhance the sensitivity of p-type semiconductors in gas-sensing applications. By utilizing a glycerate-templated synthesis approach, a unique hierarchical W-doped Co₃O₄ yolk-shell sphere (YSS)-based sensor was developed, exhibiting exceptional sensitivity toward acetone gas. The synthesized YSSs feature a yolk-shell structure with a diameter of approximately 500 nm and a large surface area of 117.46 m²/g, which allows for efficient gas interaction and high sensitivity toward acetone gas. Furthermore, the incorporation of tungsten (W), a non-noble metal, as a dopant significantly enhances the surface activity of Co₃O₄, leading to a remarkably high response of 16.5 toward 5 ppm acetone, which is substantially higher than that of the pure Co₃O₄ YSS (2.9). The W-doped Co₃O₄ YSS also exhibits excellent selectivity to other interfering gases and the ability to detect ultralow concentrations of acetone as low as 10 ppb. The proposed non-noble metal doping strategy presents a practical solution for enhancing the sensitivity and selectivity of p-type semiconductor-based gas sensors. This approach holds great potential for practical gas-sensing applications due to their affordability and abundance, making them a cost-effective and versatile alternative to noble metal-catalyzed sensors.