Advanced NOx gas sensing based on novel hybrid organic–inorganic semiconducting nanomaterial formed between pyrrole and Dawson type polyoxoanion [P2Mo18O62]6−

Abstract

Dawson-type K₆P₂Mo₁₈O₆₂·nH₂O can be used as an oxidizing agent to polymerize pyrrole and yield a hybrid organic–inorganic nanostructured material [{Py}₆(P₂Mo₁₈O₆₂)]_x. By adding the mild reducing agent potassium iodide (KI), the polymerization process was controlled to generate a hybrid material with low polypyrrole content [K₄{Py}₂(P₂Mo₁₈O₆₂)]_y. The electrical transport properties of [K₄{Py}₂(P₂Mo₁₈O₆₂)]_y displayed a perfect transistor operation suitable for gas sensing applications. Exposure of [K₄{Py}₂(P₂Mo₁₈O₆₂)]_y to various gases illustrated a selective and sensitive response to NO_x gases. In addition, an interesting extended linearity up to 5500 ppm was recorded.