Surface modification of Co₃O₄ nanosheets through Cd-doping for enhanced CO sensing performance

The detection of hazardous CO gas is an important research content in the domain of the Internet of Things (IoT). Herein, we introduced a facile metal-organic frameworks (MOFs)-templated strategy to synthesize Cd-doped Co₃O₄ nanosheets (Cd-Co₃O₄ NSs) aimed at boosting the CO-sensing performance. The synthesized Cd-Co₃O₄ NSs feature a multihole nanomeshes structure and a large specific surface area (106.579 m²·g^-1), which endows the sensing materials with favorable gas diffusion and interaction ability. Furthermore, compared with unadulterated Co₃O₄, the 2 mol % Cd-doped Co₃O₄ (2% Cd-Co₃O₄) sensor exhibits enhanced sensitivity (244%) to 100 ppm CO at 200 °C and a comparatively low experimental limit of detection (0.5 ppm/experimental value). The 2% Cd-Co₃O₄ NSs show good selectivity, reproducibility, and long-term stability. The improved CO sensitivity signal is probably owing to the stable nanomeshes construction, high surface area, and rich oxygen vacancies caused by cadmium doping. This study presents a facile avenue to promote the sensing performance of p-type metal oxide semiconductors by enhancing the surface activity of Co₃O₄ combined with morphology control and component regulation.