Single-atom transition metals doping in N-doped hollow carbon spheres for high-performance organic gas sensing

Organic gas sensors have attracted considerable interest owing to their promising applications in environmental monitoring and industrial operations. However, the inherent low mobility and stability of conjugated polymers limit their effectiveness in gas sensing. In this study, we explore the enhancement of organic gas sensor performance by doping transition metals (Ni and Cu) into nitrogen-doped 3D hollow carbon spheres (NHCS). NHCS, a carbon-based material, stands out for its exceptional electrical conductivity, extensive surface area, and robust chemical stability, positioning it as a promising choice for sensor applications. Its gas-sensing efficiency can be further enhanced through the incorporation of single-atom transition-metal dopants. Our experimental results demonstrate that the high porosity of NHCS serves as an efficient gas diffusion channel, enabling enhanced penetration of gas molecules into the active layer. Moreover, the single-atom transition-metal sites exhibit strong chemisorption properties, surpassing the binding strength of physical adsorption. The NHCS-blended sensor co- doped with Ni and Cu exhibited the most promising gas-sensing performance. This improvement is attributed to the synergistic effects of nitrogen doping and the dual transition-metal dopants, which contribute to selective NO2 detection. These results indicate a valuable direction for advancing gas-sensing devices with enhanced sensitivity and selectivity.